Merge mozilla-inbound to mozilla-central a=merge

.eslintignore

@@ -190,6 +190,7 @@ dom/grid/**
 dom/html/**
 dom/ipc/**
 dom/jsurl/**
+dom/localstorage/**
 dom/manifest/**
 dom/media/test/**
 dom/media/tests/**

browser/base/content/test/sanitize/browser_cookiePermission.js

@@ -277,7 +277,7 @@ add_task(async function deleteStorageInAboutURL() {
 
   let principal = Services.scriptSecurityManager.createCodebasePrincipalFromOrigin("about:newtab");
   await new Promise(aResolve => {
-    let req = Services.qms.clearStoragesForPrincipal(principal, null, false);
+    let req = Services.qms.clearStoragesForPrincipal(principal);
     req.callback = () => { aResolve(); };
   });
 });
@@ -313,7 +313,7 @@ add_task(async function deleteStorageOnlyCustomPermissionInAboutURL() {
 
   let principal = Services.scriptSecurityManager.createCodebasePrincipalFromOrigin("about:newtab");
   await new Promise(aResolve => {
-    let req = Services.qms.clearStoragesForPrincipal(principal, null, false);
+    let req = Services.qms.clearStoragesForPrincipal(principal);
     req.callback = () => { aResolve(); };
   });
 

browser/base/content/test/webextensions/browser.ini

@@ -2,7 +2,6 @@
 support-files =
   head.js
   file_install_extensions.html
-  browser_legacy.xpi
   browser_legacy_webext.xpi
   browser_webext_permissions.xpi
   browser_webext_nopermissions.xpi

browser/base/content/test/webextensions/browser_extension_update_background_noprompt.js

@@ -1,7 +1,6 @@
 const {AddonManagerPrivate} = ChromeUtils.import("resource://gre/modules/AddonManager.jsm", {});
 
 const ID_PERMS = "update_perms@tests.mozilla.org";
-const ID_LEGACY = "legacy_update@tests.mozilla.org";
 const ID_ORIGINS = "update_origins@tests.mozilla.org";
 
 function getBadgeStatus() {
@@ -80,11 +79,6 @@ async function testNoPrompt(origUrl, id) {
 add_task(() => testNoPrompt(`${BASE}/browser_webext_update_perms1.xpi`,
                             ID_PERMS));
 
-// Test that an update from a legacy extension to a webextension
-// doesn't show a prompt even when the webextension uses
-// promptable required permissions.
-add_task(() => testNoPrompt(`${BASE}/browser_legacy.xpi`, ID_LEGACY));
-
 // Test that an update that narrows origin permissions is just applied without
 // showing a notification promt
 add_task(() => testNoPrompt(`${BASE}/browser_webext_update_origins1.xpi`,

browser/base/content/test/webextensions/browser_update_interactive_noprompt.js

@@ -51,11 +51,6 @@ async function testUpdateNoPrompt(filename, id,
   await addon.uninstall();
 }
 
-// Test that we don't see a prompt when updating from a legacy
-// extension to a webextension.
-add_task(() => testUpdateNoPrompt("browser_legacy.xpi",
-                                  "legacy_update@tests.mozilla.org", "1.1"));
-
 // Test that we don't see a prompt when no new promptable permissions
 // are added.
 add_task(() => testUpdateNoPrompt("browser_webext_update_perms1.xpi",

browser/components/aboutconfig/content/aboutconfig.css

@@ -14,6 +14,7 @@
   background-position: 9px center;
   background-size: 12px 12px;
   padding-left: 30px;
+  z-index: 1;
 }
 
 #prefs {
@@ -39,11 +40,23 @@
   font-weight: bold;
 }
 
+#prefs > tr.locked {
+  opacity: 0.4;
+  background-image: url("chrome://browser/skin/preferences/in-content/privacy-security.svg");
+  background-repeat: no-repeat;
+  background-position: 9px center;
+  background-size: 16px 16px;
+}
+
 #prefs > tr > td {
   padding: 4px;
   width: 50%;
 }
 
+#prefs > tr > td.cell-name {
+  padding-inline-start: 30px;
+}
+
 .cell-value {
   word-break: break-all;
 }

browser/components/aboutconfig/content/aboutconfig.js

@@ -19,14 +19,16 @@ function onLoad() {
     let hasUserValue = Services.prefs.prefHasUserValue(name);
     let pref = {
       name,
-      value: Preferences.get(name),
       hasUserValue,
       hasDefaultValue: hasUserValue ? prefHasDefaultValue(name) : true,
+      isLocked: Services.prefs.prefIsLocked(name),
     };
-    // Try in case it's a localized string.
+    // Try in case it's a localized string or locked user added pref
-    // Throws an exception if there is no equivalent value in the localized files for the pref.
     // If an execption is thrown the pref value is set to the empty string.
     try {
+      // Throws an exception in case locked user added pref without default value
+      pref.value = Preferences.get(name);
+      // Throws an exception if there is no equivalent value in the localized files for the pref.
       if (!pref.hasUserValue && /^chrome:\/\/.+\/locale\/.+\.properties/.test(pref.value)) {
         pref.value = Services.prefs.getComplexValue(name, Ci.nsIPrefLocalizedString).data;
       }
@@ -121,6 +123,9 @@ function createPrefsFragment(prefArray) {
     if (pref.hasUserValue) {
       row.classList.add("has-user-value");
     }
+    if (pref.isLocked) {
+      row.classList.add("locked");
+    }
     row.setAttribute("aria-label", pref.name);
 
     row.appendChild(getPrefRow(pref));
@@ -135,6 +140,7 @@ function createNewPrefFragment(name) {
   row.classList.add("has-user-value");
   row.setAttribute("aria-label", name);
   let nameCell = document.createElement("td");
+  nameCell.className = "cell-name";
   nameCell.append(name);
   row.appendChild(nameCell);
 
@@ -164,6 +170,7 @@ function createNewPrefFragment(name) {
 function getPrefRow(pref) {
   let rowFragment = document.createDocumentFragment();
   let nameCell = document.createElement("td");
+  nameCell.className = "cell-name";
   // Add <wbr> behind dots to prevent line breaking in random mid-word places.
   let parts = pref.name.split(".");
   for (let i = 0; i < parts.length - 1; i++) {
@@ -187,11 +194,14 @@ function getPrefRow(pref) {
     document.l10n.setAttributes(button, "about-config-pref-edit");
     button.className = "button-edit";
   }
+  if (pref.isLocked) {
+    button.disabled = true;
+  }
   editCell.appendChild(button);
   rowFragment.appendChild(editCell);
 
   let buttonCell = document.createElement("td");
-  if (pref.hasUserValue) {
+  if (!pref.isLocked && pref.hasUserValue) {
     let resetButton = document.createElement("button");
     if (!pref.hasDefaultValue) {
       document.l10n.setAttributes(resetButton, "about-config-pref-delete");
@@ -201,6 +211,7 @@ function getPrefRow(pref) {
     }
     buttonCell.appendChild(resetButton);
   }
+
   rowFragment.appendChild(buttonCell);
   return rowFragment;
 }

browser/components/aboutconfig/test/browser/browser.ini

@@ -5,3 +5,5 @@
 skip-if = debug # Bug 1507747
 [browser_search.js]
 skip-if = debug # Bug 1507747
+[browser_locked.js]
+

browser/components/aboutconfig/test/browser/browser_locked.js

@@ -0,0 +1,70 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const PAGE_URL = "chrome://browser/content/aboutconfig/aboutconfig.html";
+
+add_task(async function setup() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["test.aboutconfig.a", "some value"],
+    ],
+  });
+});
+
+add_task(async function test_locked() {
+  registerCleanupFunction(() => {
+    Services.prefs.unlockPref("browser.search.searchEnginesURL");
+    Services.prefs.unlockPref("test.aboutconfig.a");
+    Services.prefs.unlockPref("accessibility.AOM.enabled");
+  });
+
+  Services.prefs.lockPref("browser.search.searchEnginesURL");
+  Services.prefs.lockPref("test.aboutconfig.a");
+  Services.prefs.lockPref("accessibility.AOM.enabled");
+  await BrowserTestUtils.withNewTab({
+    gBrowser,
+    url: PAGE_URL,
+  }, async browser => {
+    await ContentTask.spawn(browser, null, () => {
+      let list = [...content.document.getElementById("prefs")
+        .getElementsByTagName("tr")];
+      function getRow(name) {
+        return list.find(row => row.querySelector("td").textContent == name);
+      }
+      function getValue(name) {
+          return getRow(name).querySelector("td.cell-value").textContent;
+      }
+      function getButton(name) {
+        return getRow(name).querySelector("button");
+      }
+
+      // Test locked default string pref.
+      let lockedPref = getRow("browser.search.searchEnginesURL");
+      Assert.ok(lockedPref.classList.contains("locked"));
+      Assert.equal(getValue("browser.search.searchEnginesURL"), "https://addons.mozilla.org/%LOCALE%/firefox/search-engines/");
+      Assert.ok(getButton("browser.search.searchEnginesURL").classList.contains("button-edit"));
+      Assert.equal(getButton("browser.search.searchEnginesURL").disabled, true);
+
+      // Test locked default boolean pref.
+      lockedPref = getRow("accessibility.AOM.enabled");
+      Assert.ok(lockedPref.classList.contains("locked"));
+      Assert.equal(getValue("accessibility.AOM.enabled"), "false");
+      Assert.ok(getButton("accessibility.AOM.enabled").classList.contains("button-toggle"));
+      Assert.equal(getButton("accessibility.AOM.enabled").disabled, true);
+
+      // Test locked user added pref.
+      lockedPref = getRow("test.aboutconfig.a");
+      Assert.ok(lockedPref.classList.contains("locked"));
+      Assert.equal(getValue("test.aboutconfig.a"), "");
+      Assert.ok(getButton("test.aboutconfig.a").classList.contains("button-edit"));
+      Assert.equal(getButton("test.aboutconfig.a").disabled, true);
+
+      // Test pref not locked
+      let unlockedPref = getRow("accessibility.indicator.enabled");
+      Assert.equal(unlockedPref.classList.contains("locked"), false);
+      Assert.equal(getValue("accessibility.indicator.enabled"), "false");
+      Assert.ok(getButton("accessibility.indicator.enabled").classList.contains("button-toggle"));
+      Assert.equal(getButton("accessibility.indicator.enabled").disabled, false);
+    });
+  });
+});

browser/components/contextualidentity/test/browser/browser_forgetAPI_quota_clearStoragesForPrincipal.js

@@ -92,6 +92,10 @@ async function checkIndexedDB(browser) {
     } catch (e) {
       is(e.name, "NotFoundError", "The indexedDB does not exist as expected");
     }
+
+    db.close();
+
+    content.indexedDB.deleteDatabase("idb");
   });
 }
 
@@ -127,7 +131,12 @@ add_task(async function test_quota_clearStoragesForPrincipal() {
   let httpURI = caUtils.makeURI("http://" + TEST_HOST);
   let httpPrincipal = Services.scriptSecurityManager
                               .createCodebasePrincipal(httpURI, {});
-  Services.qms.clearStoragesForPrincipal(httpPrincipal, null, true);
+  let clearRequest = Services.qms.clearStoragesForPrincipal(httpPrincipal, null, null, true);
+  await new Promise(resolve => {
+    clearRequest.callback = () => {
+      resolve();
+    };
+  });
 
   for (let userContextId of Object.keys(USER_CONTEXTS)) {
     // Open our tab in the given user context.

browser/components/extensions/parent/ext-browsingData.js

@@ -77,22 +77,26 @@ const clearHistory = options => {
 const clearIndexedDB = async function(options) {
   let promises = [];
 
-  await new Promise(resolve => {
+  await new Promise((resolve, reject) => {
     quotaManagerService.getUsage(request => {
       if (request.resultCode != Cr.NS_OK) {
-        // We are probably shutting down. We don't want to propagate the error,
+        reject({message: "Clear indexedDB failed"});
-        // rejecting the promise.
-        resolve();
         return;
       }
 
       for (let item of request.result) {
         let principal = Services.scriptSecurityManager.createCodebasePrincipalFromOrigin(item.origin);
-        let uri = principal.URI;
+        let scheme = principal.URI.scheme;
-        if (uri.scheme == "http" || uri.scheme == "https" || uri.scheme == "file") {
+        if (scheme == "http" || scheme == "https" || scheme == "file") {
-          promises.push(new Promise(r => {
+          promises.push(new Promise((resolve, reject) => {
-            let req = quotaManagerService.clearStoragesForPrincipal(principal, null, false);
+            let clearRequest = quotaManagerService.clearStoragesForPrincipal(principal, null, "idb");
-            req.callback = () => { r(); };
+            clearRequest.callback = () => {
+              if (clearRequest.resultCode == Cr.NS_OK) {
+                resolve();
+              } else {
+                reject({message: "Clear indexedDB failed"});
+              }
+            };
           }));
         }
       }
@@ -109,6 +113,46 @@ const clearLocalStorage = async function(options) {
     return Promise.reject(
       {message: "Firefox does not support clearing localStorage with 'since'."});
   }
+
+  if (Services.lsm.nextGenLocalStorageEnabled) {
+    // Ideally we could reuse the logic in Sanitizer.jsm or nsIClearDataService,
+    // but this API exposes an ability to wipe data at a much finger granularity
+    // than those APIs.  So custom logic is used here to wipe only the QM
+    // localStorage client (when in use).
+
+    let promises = [];
+
+    await new Promise((resolve, reject) => {
+      quotaManagerService.getUsage(request => {
+        if (request.resultCode != Cr.NS_OK) {
+          reject({message: "Clear localStorage failed"});
+          return;
+        }
+
+        for (let item of request.result) {
+          let principal = Services.scriptSecurityManager.createCodebasePrincipalFromOrigin(item.origin);
+          let host = principal.URI.hostPort;
+          if (!options.hostnames || options.hostnames.includes(host)) {
+            promises.push(new Promise((resolve, reject) => {
+              let clearRequest = quotaManagerService.clearStoragesForPrincipal(principal, "default", "ls");
+              clearRequest.callback = () => {
+                if (clearRequest.resultCode == Cr.NS_OK) {
+                  resolve();
+                } else {
+                  reject({message: "Clear localStorage failed"});
+                }
+              };
+            }));
+          }
+        }
+
+        resolve();
+      });
+    });
+
+    return Promise.all(promises);
+  }
+
   if (options.hostnames) {
     for (let hostname of options.hostnames) {
       Services.obs.notifyObservers(null, "extension:purge-localStorage", hostname);

browser/components/extensions/test/browser/browser_ext_browsingData_indexedDB.js

@@ -53,6 +53,9 @@ add_task(async function testIndexedDB() {
       let origins = [];
       Services.qms.getUsage(request => {
         for (let i = 0; i < request.result.length; ++i) {
+          if (request.result[i].usage === 0) {
+            continue;
+          }
           if (request.result[i].origin.startsWith("http://mochi.test") ||
               request.result[i].origin.startsWith("http://example.com")) {
             origins.push(request.result[i].origin);

browser/components/extensions/test/browser/browser_ext_browsingData_localStorage.js

@@ -60,6 +60,9 @@ add_task(async function testLocalStorage() {
     await browser.browsingData.remove({}, {localStorage: true});
     await sendMessageToTabs(tabs, "checkLocalStorageCleared");
 
+    // Cleanup (checkLocalStorageCleared creates empty LS databases).
+    await browser.browsingData.removeLocalStorage({});
+
     browser.tabs.remove(tabs.map(tab => tab.id));
 
     browser.test.notifyPass("done");

browser/components/preferences/in-content/tests/siteData/browser.ini

@@ -9,7 +9,7 @@ support-files =
 
 [browser_clearSiteData.js]
 [browser_siteData.js]
-skip-if = (os == 'linux' && debug) # Bug 1439332
+skip-if = (os == 'linux' && debug) || verify # Bug 1439332 and bug 1436395
 [browser_siteData2.js]
 [browser_siteData3.js]
 [browser_siteData_multi_select.js]

browser/components/preferences/in-content/tests/siteData/browser_siteData.js

@@ -44,7 +44,7 @@ add_task(async function() {
   await new Promise(resolve => {
     let principal = Services.scriptSecurityManager
                             .createCodebasePrincipalFromOrigin(TEST_QUOTA_USAGE_ORIGIN);
-    let request = Services.qms.clearStoragesForPrincipal(principal, null, true);
+    let request = Services.qms.clearStoragesForPrincipal(principal, null, null, true);
     request.callback = resolve;
   });
 

browser/modules/SiteDataManager.jsm

@@ -304,7 +304,7 @@ var SiteDataManager = {
         // We are clearing *All* across OAs so need to ensure a principal without suffix here,
         // or the call of `clearStoragesForPrincipal` would fail.
         principal = Services.scriptSecurityManager.createCodebasePrincipalFromOrigin(originNoSuffix);
-        let request = this._qms.clearStoragesForPrincipal(principal, null, true);
+        let request = this._qms.clearStoragesForPrincipal(principal, null, null, true);
         request.callback = resolve;
       }));
     }

caps/ContentPrincipal.cpp

@@ -396,8 +396,17 @@ GetSpecialBaseDomain(const nsCOMPtr<nsIURI>& aCodebase,
 {
   *aHandled = false;
 
-  // For a file URI, we return the file path.
+  // Special handling for a file URI.
   if (NS_URIIsLocalFile(aCodebase)) {
+    // If strict file origin policy is not in effect, all local files are
+    // considered to be same-origin, so return a known dummy domain here.
+    if (!nsScriptSecurityManager::GetStrictFileOriginPolicy()) {
+      *aHandled = true;
+      aBaseDomain.AssignLiteral("UNIVERSAL_FILE_URI_ORIGIN");
+      return NS_OK;
+    }
+
+    // Otherwise, we return the file path.
     nsCOMPtr<nsIURL> url = do_QueryInterface(aCodebase);
 
     if (url) {

config/check_macroassembler_style.py

@@ -48,6 +48,8 @@ def get_normalized_signatures(signature, fileAnnot=None):
     signature = signature.replace(';', ' ')
     # Normalize spaces.
     signature = re.sub(r'\s+', ' ', signature).strip()
+    # Remove new-line induced spaces after opening braces.
+    signature = re.sub(r'\(\s+', '(', signature).strip()
     # Match arguments, and keep only the type.
     signature = reMatchArg.sub('\g<type>', signature)
     # Remove class name
@@ -144,45 +146,62 @@ def get_macroassembler_definitions(filename):
         return []
 
     style_section = False
-    code_section = False
     lines = ''
     signatures = []
     with open(filename) as f:
         for line in f:
             if '//{{{ check_macroassembler_style' in line:
+                if style_section:
+                    raise 'check_macroassembler_style section already opened.'
                 style_section = True
+                braces_depth = 0
             elif '//}}} check_macroassembler_style' in line:
                 style_section = False
             if not style_section:
                 continue
 
+            # Remove comments from the processed line.
             line = re.sub(r'//.*', '', line)
-            if line.startswith('{') or line.strip() == "{}":
+
+            # Locate and count curly braces.
+            open_curly_brace = line.find('{')
+            was_braces_depth = braces_depth
+            braces_depth = braces_depth + line.count('{') - line.count('}')
+
+            # Raise an error if the check_macroassembler_style macro is used
+            # across namespaces / classes scopes.
+            if braces_depth < 0:
+                raise 'check_macroassembler_style annotations are not well scoped.'
+
+            # If the current line contains an opening curly brace, check if
+            # this line combines with the previous one can be identified as a
+            # MacroAssembler function signature.
+            if open_curly_brace != -1 and was_braces_depth == 0:
+                lines = lines + line[:open_curly_brace]
                 if 'MacroAssembler::' in lines:
                     signatures.extend(
                         get_normalized_signatures(lines, fileAnnot))
-                if line.strip() != "{}":  # Empty declaration, no need to declare
-                    # a new code section
-                    code_section = True
-                continue
-            if line.startswith('}'):
-                code_section = False
                 lines = ''
                 continue
-            if code_section:
-                continue
 
-            if len(line.strip()) == 0:
+            # We do not aggregate any lines if we are scanning lines which are
-                lines = ''
+            # in-between a set of curly braces.
+            if braces_depth > 0:
                 continue
+            if was_braces_depth != 0:
+                line = line[line.rfind('}') + 1:]
+
+            # This logic is used to remove template instantiation, static
+            # variable definitions and function declaration from the next
+            # function definition.
+            last_semi_colon = line.rfind(';')
+            if last_semi_colon != -1:
+                lines = ''
+                line = line[last_semi_colon + 1:]
+
+            # Aggregate lines of non-braced text, which corresponds to the space
+            # where we are expecting to find function definitions.
             lines = lines + line
-            # Continue until we have a complete declaration
-            if '{' not in lines:
-                continue
-            # Skip variable declarations
-            if ')' not in lines:
-                lines = ''
-                continue
 
     return signatures
 
@@ -201,14 +220,17 @@ def get_macroassembler_declaration(filename):
                 continue
 
             line = re.sub(r'//.*', '', line)
-            if len(line.strip()) == 0:
+            if len(line.strip()) == 0 or 'public:' in line or 'private:' in line:
                 lines = ''
                 continue
             lines = lines + line
+
             # Continue until we have a complete declaration
             if ';' not in lines:
                 continue
-            # Skip variable declarations
+
+            # Skip member declarations: which are lines ending with a
+            # semi-colon without any list of arguments.
             if ')' not in lines:
                 lines = ''
                 continue

devtools/client/aboutdebugging/test/browser.ini

@@ -23,6 +23,8 @@ support-files =
   !/devtools/client/shared/test/telemetry-test-helpers.js
 
 [browser_addons_debug_bootstrapped.js]
+# To be removed in bug 1497264
+skip-if = true
 [browser_addons_debug_info.js]
 [browser_addons_debug_webextension.js]
 tags = webextensions
@@ -34,11 +36,16 @@ tags = webextensions
 skip-if = (verify && debug) || (debug && os == "linux" && bits == 64) # verify: crashes on shutdown, timeouts linux debug Bug 1299001
 tags = webextensions
 [browser_addons_debugging_initial_state.js]
+# To be removed or updated in bug 1497264
+skip-if = true
 [browser_addons_install.js]
-skip-if = verify && debug
+# To be updated in bug 1497264 (was "verify && debug")
+skip-if = true
 [browser_addons_reload.js]
 [browser_addons_remove.js]
 [browser_addons_toggle_debug.js]
+# To be removed or updated in bug 1497264
+skip-if = true
 [browser_page_not_found.js]
 [browser_service_workers.js]
 [browser_service_workers_fetch_flag.js]

devtools/client/aboutdebugging/test/browser_addons_debug_info.js

@@ -13,6 +13,8 @@ function testFilePath(container, expectedFilePath) {
   is(filePath.previousElementSibling.textContent, "Location", "file path has label");
 }
 
+// Remove in Bug 1497264
+/*
 add_task(async function testLegacyAddon() {
   const addonId = "test-devtools@mozilla.org";
   const addonName = "test-devtools";
@@ -32,6 +34,7 @@ add_task(async function testLegacyAddon() {
 
   await closeAboutDebugging(tab);
 });
+*/
 
 add_task(async function testWebExtension() {
   const addonId = "test-devtools-webextension-nobg@mozilla.org";

devtools/client/aboutdebugging/test/browser_addons_install.js

@@ -7,9 +7,6 @@ loader.lazyImporter(this, "AddonTestUtils",
 
 AddonTestUtils.initMochitest(this);
 
-const ADDON_ID = "test-devtools@mozilla.org";
-const ADDON_NAME = "test-devtools";
-
 function mockFilePicker(window, file) {
   // Mock the file picker to select a test addon
   const MockFilePicker = SpecialPowers.MockFilePicker;
@@ -35,6 +32,9 @@ function promiseWriteWebManifestForExtension(manifest, dir) {
 }
 
 add_task(async function testLegacyInstallSuccess() {
+  const ADDON_ID = "test-devtools@mozilla.org";
+  const ADDON_NAME = "test-devtools";
+
   const { tab, document } = await openAboutDebugging("addons");
   await waitForInitialAddonList(document);
 

devtools/client/aboutdebugging/test/browser_addons_reload.js

@@ -3,7 +3,6 @@
 "use strict";
 
 const ADDON_ID = "test-devtools@mozilla.org";
-const ADDON_NAME = "test-devtools";
 
 const PACKAGED_ADDON_ID = "bug1273184@tests";
 const PACKAGED_ADDON_NAME = "bug 1273184";
@@ -60,7 +59,10 @@ class TempWebExt {
   }
 }
 
+// Remove in Bug 1497264
+/*
 add_task(async function reloadButtonReloadsAddon() {
+  const ADDON_NAME = "test-devtools";
   const { tab, document, window } = await openAboutDebugging("addons");
   const { AboutDebugging } = window;
   await waitForInitialAddonList(document);
@@ -96,6 +98,7 @@ add_task(async function reloadButtonReloadsAddon() {
   await tearDownAddon(AboutDebugging, reloadedAddon);
   await closeAboutDebugging(tab);
 });
+*/
 
 add_task(async function reloadButtonRefreshesMetadata() {
   const { tab, document, window } = await openAboutDebugging("addons");

devtools/client/aboutdebugging/test/browser_addons_remove.js

@@ -12,6 +12,8 @@ function getRemoveButton(document, id) {
   return document.querySelector(`[data-addon-id="${id}"] .uninstall-button`);
 }
 
+// Remove in Bug 1497264
+/*
 add_task(async function removeLegacyExtension() {
   const addonID = "test-devtools@mozilla.org";
   const addonName = "test-devtools";
@@ -36,6 +38,7 @@ add_task(async function removeLegacyExtension() {
 
   await closeAboutDebugging(tab);
 });
+*/
 
 add_task(async function removeWebextension() {
   const addonID = "test-devtools-webextension@mozilla.org";

devtools/client/inspector/flexbox/flexbox.js

@@ -401,7 +401,7 @@ class FlexboxInspector {
    *         highlighter is toggled on/off for.
    */
   onToggleFlexboxHighlighter(node) {
-    this.highlighters.toggleFlexboxHighlighter(node);
+    this.highlighters.toggleFlexboxHighlighter(node, "layout");
     this.store.dispatch(updateFlexboxHighlighted(node !==
       this.highlighters.flexboxHighlighterShow));
   }

devtools/client/inspector/flexbox/test/browser.ini

@@ -26,6 +26,7 @@ support-files =
 [browser_flexbox_empty_state.js]
 [browser_flexbox_highlighter_color_picker_on_ESC.js]
 [browser_flexbox_highlighter_color_picker_on_RETURN.js]
+[browser_flexbox_highlighter_opened_telemetry.js]
 [browser_flexbox_item_list_01.js]
 [browser_flexbox_item_list_02.js]
 [browser_flexbox_item_list_updates_on_change.js]

devtools/client/inspector/flexbox/test/browser_flexbox_highlighter_opened_telemetry.js

@@ -0,0 +1,32 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that the telemetry is correct when the flexbox highlighter is activated from
+// the layout view.
+
+const TEST_URI = URL_ROOT + "doc_flexbox_specific_cases.html";
+
+add_task(async function() {
+  await addTab(TEST_URI);
+  startTelemetry();
+  const { inspector, flexboxInspector } = await openLayoutView();
+  const { document: doc } = flexboxInspector;
+  const { highlighters, store } = inspector;
+
+  const onFlexHighlighterToggleRendered = waitForDOM(doc, "#flexbox-checkbox-toggle");
+  await selectNode("#container", inspector);
+  const [flexHighlighterToggle] = await onFlexHighlighterToggleRendered;
+
+  await toggleHighlighterON(flexHighlighterToggle, highlighters, store);
+  await toggleHighlighterOFF(flexHighlighterToggle, highlighters, store);
+
+  checkResults();
+});
+
+function checkResults() {
+  checkTelemetry("devtools.layout.flexboxhighlighter.opened", "", 1, "scalar");
+  checkTelemetry("DEVTOOLS_FLEXBOX_HIGHLIGHTER_TIME_ACTIVE_SECONDS", "", null,
+    "hasentries");
+}

devtools/client/inspector/flexbox/test/head.js

@@ -2,6 +2,7 @@
 /* Any copyright is dedicated to the Public Domain.
  http://creativecommons.org/publicdomain/zero/1.0/ */
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
+/* import-globals-from ../../../shared/test/telemetry-test-helpers.js */
 /* import-globals-from ../../test/head.js */
 "use strict";
 

devtools/client/inspector/grids/test/browser.ini

@@ -39,6 +39,7 @@ skip-if = (verify && (os == 'win'))
 [browser_grids_grid-outline-writing-mode.js]
 skip-if = (verify && (os == 'win'))
 [browser_grids_highlighter-setting-rules-grid-toggle.js]
+[browser_grids_highlighter-toggle-telemetry.js]
 [browser_grids_number-of-css-grids-telemetry.js]
 [browser_grids_persist-color-palette.js]
 [browser_grids_restored-after-reload.js]

devtools/client/inspector/grids/test/browser_grids_highlighter-toggle-telemetry.js

@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that the telemetry count is correct when the grid highlighter is activated from
+// the layout view.
+
+const TEST_URI = `
+  <style type='text/css'>
+    #grid {
+      display: grid;
+    }
+  </style>
+  <div id="grid">
+    <div id="cell1">cell1</div>
+    <div id="cell2">cell2</div>
+  </div>
+`;
+
+add_task(async function() {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  startTelemetry();
+  const { gridInspector, inspector } = await openLayoutView();
+  const { document: doc } = gridInspector;
+  const { highlighters, store } = inspector;
+
+  await selectNode("#grid", inspector);
+  const gridList = doc.getElementById("grid-list");
+  const checkbox = gridList.children[0].querySelector("input");
+
+  info("Toggling ON the CSS grid highlighter from the layout panel.");
+  const onHighlighterShown = highlighters.once("grid-highlighter-shown");
+  const onCheckboxChange = waitUntilState(store, state =>
+    state.grids.length == 1 &&
+    state.grids[0].highlighted);
+  checkbox.click();
+  await onHighlighterShown;
+  await onCheckboxChange;
+
+  checkResults();
+});
+
+function checkResults() {
+  checkTelemetry("devtools.grid.gridinspector.opened", "", 1, "scalar");
+}

devtools/client/inspector/markup/test/browser.ini

@@ -135,8 +135,10 @@ skip-if = true # Bug 1177550
 [browser_markup_events_source_map.js]
 [browser_markup_events-windowed-host.js]
 [browser_markup_flex_display_badge.js]
+[browser_markup_flex_display_badge_telemetry.js]
 [browser_markup_grid_display_badge_01.js]
 [browser_markup_grid_display_badge_02.js]
+[browser_markup_grid_display_badge_telemetry.js]
 [browser_markup_links_01.js]
 [browser_markup_links_02.js]
 [browser_markup_links_03.js]

devtools/client/inspector/markup/test/browser_markup_flex_display_badge_telemetry.js

@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that the telemetry is correct when the flexbox highlighter is activated from
+// the markup view.
+
+const TEST_URI = `
+  <style type="text/css">
+    #flex {
+      display: flex;
+    }
+  </style>
+  <div id="flex"></div>
+`;
+
+add_task(async function() {
+  await pushPref("devtools.inspector.flexboxHighlighter.enabled", true);
+  await pushPref("devtools.flexboxinspector.enabled", true);
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  startTelemetry();
+  const { inspector } = await openLayoutView();
+  const { highlighters } = inspector;
+
+  await selectNode("#flex", inspector);
+  const flexContainer = await getContainerForSelector("#flex", inspector);
+  const flexDisplayBadge = flexContainer.elt.querySelector(
+    ".inspector-badge.interactive[data-display]");
+
+  info("Toggling ON the flexbox highlighter from the flex display badge.");
+  const onHighlighterShown = highlighters.once("flexbox-highlighter-shown");
+  flexDisplayBadge.click();
+  await onHighlighterShown;
+
+  info("Toggling OFF the flexbox highlighter from the flex display badge.");
+  const onHighlighterHidden = highlighters.once("flexbox-highlighter-hidden");
+  flexDisplayBadge.click();
+  await onHighlighterHidden;
+
+  checkResults();
+});
+
+function checkResults() {
+  checkTelemetry("devtools.markup.flexboxhighlighter.opened", "", 1, "scalar");
+  checkTelemetry("DEVTOOLS_FLEXBOX_HIGHLIGHTER_TIME_ACTIVE_SECONDS", "", null,
+    "hasentries");
+}

devtools/client/inspector/markup/test/browser_markup_grid_display_badge_telemetry.js

@@ -0,0 +1,43 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that the telemetry count is correct when the grid highlighter is activated from
+// the markup view.
+
+const TEST_URI = `
+  <style type="text/css">
+    #grid {
+      display: grid;
+    }
+  </style>
+  <div id="grid"></div>
+`;
+
+add_task(async function() {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  startTelemetry();
+  const { inspector } = await openLayoutView();
+  const { highlighters, store } = inspector;
+
+  await selectNode("#grid", inspector);
+  const gridContainer = await getContainerForSelector("#grid", inspector);
+  const gridDisplayBadge = gridContainer.elt.querySelector(
+    ".inspector-badge.interactive[data-display]");
+
+  info("Toggling ON the CSS grid highlighter from the grid display badge.");
+  const onHighlighterShown = highlighters.once("grid-highlighter-shown");
+  const onCheckboxChange = waitUntilState(store, state =>
+    state.grids.length === 1 &&
+    state.grids[0].highlighted);
+  gridDisplayBadge.click();
+  await onHighlighterShown;
+  await onCheckboxChange;
+
+  checkResults();
+});
+
+function checkResults() {
+  checkTelemetry("devtools.markup.gridinspector.opened", "", 1, "scalar");
+}

devtools/client/inspector/markup/test/head.js

@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
+/* import-globals-from ../../../shared/test/telemetry-test-helpers.js */
 /* import-globals-from ../../test/head.js */
 "use strict";
 

devtools/client/inspector/markup/views/element-editor.js

@@ -749,7 +749,7 @@ ElementEditor.prototype = {
       this.stopTrackingFlexboxHighlighterEvents();
 
       this._displayBadge.classList.toggle("active");
-      await this.highlighters.toggleFlexboxHighlighter(this.node);
+      await this.highlighters.toggleFlexboxHighlighter(this.node, "markup");
 
       this.startTrackingFlexboxHighlighterEvents();
     }

devtools/client/inspector/rules/test/browser.ini

@@ -166,6 +166,7 @@ skip-if = (os == "win" && debug) # bug 963492: win.
 [browser_rules_flexbox-highlighter-on-navigate.js]
 [browser_rules_flexbox-highlighter-on-reload.js]
 [browser_rules_flexbox-highlighter-restored-after-reload.js]
+[browser_rules_flexbox-toggle-telemetry.js]
 [browser_rules_flexbox-toggle_01.js]
 [browser_rules_flexbox-toggle_01b.js]
 [browser_rules_flexbox-toggle_02.js]
@@ -176,6 +177,7 @@ skip-if = (os == "win" && debug) # bug 963492: win.
 [browser_rules_grid-highlighter-on-navigate.js]
 [browser_rules_grid-highlighter-on-reload.js]
 [browser_rules_grid-highlighter-restored-after-reload.js]
+[browser_rules_grid-toggle-telemetry.js]
 [browser_rules_grid-toggle_01.js]
 [browser_rules_grid-toggle_01b.js]
 [browser_rules_grid-toggle_02.js]

devtools/client/inspector/rules/test/browser_rules_flexbox-toggle-telemetry.js

@@ -0,0 +1,46 @@
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that the telemetry is correct when the flexbox highlighter is activated from
+// the rules view.
+
+const TEST_URI = `
+  <style type='text/css'>
+    #flex {
+      display: flex;
+    }
+  </style>
+  <div id="flex"></div>
+`;
+
+add_task(async function() {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  startTelemetry();
+  const {inspector, view} = await openRuleView();
+  const {highlighters} = view;
+
+  await selectNode("#flex", inspector);
+  const container = getRuleViewProperty(view, "#flex", "display").valueSpan;
+  const flexboxToggle = container.querySelector(".ruleview-flex");
+
+  info("Toggling ON the flexbox highlighter from the rule-view.");
+  const onHighlighterShown = highlighters.once("flexbox-highlighter-shown");
+  flexboxToggle.click();
+  await onHighlighterShown;
+
+  info("Toggling OFF the flexbox highlighter from the rule-view.");
+  const onHighlighterHidden = highlighters.once("flexbox-highlighter-hidden");
+  flexboxToggle.click();
+  await onHighlighterHidden;
+
+  checkResults();
+});
+
+function checkResults() {
+  checkTelemetry("devtools.rules.flexboxhighlighter.opened", "", 1, "scalar");
+  checkTelemetry("DEVTOOLS_FLEXBOX_HIGHLIGHTER_TIME_ACTIVE_SECONDS", "", null,
+    "hasentries");
+}

devtools/client/inspector/rules/test/browser_rules_grid-toggle-telemetry.js

@@ -0,0 +1,42 @@
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that the telemetry count is correct when the grid highlighter is activated from
+// the rules view.
+
+const TEST_URI = `
+  <style type='text/css'>
+    #grid {
+      display: grid;
+    }
+  </style>
+  <div id="grid">
+    <div id="cell1">cell1</div>
+    <div id="cell2">cell2</div>
+  </div>
+`;
+
+add_task(async function() {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  startTelemetry();
+  const {inspector, view} = await openRuleView();
+  const highlighters = view.highlighters;
+
+  await selectNode("#grid", inspector);
+  const container = getRuleViewProperty(view, "#grid", "display").valueSpan;
+  const gridToggle = container.querySelector(".ruleview-grid");
+
+  info("Toggling ON the CSS grid highlighter from the rule-view.");
+  const onHighlighterShown = highlighters.once("grid-highlighter-shown");
+  gridToggle.click();
+  await onHighlighterShown;
+
+  checkResults();
+});
+
+function checkResults() {
+  checkTelemetry("devtools.rules.gridinspector.opened", "", 1, "scalar");
+}

devtools/client/inspector/rules/test/head.js

@@ -2,6 +2,7 @@
 /* Any copyright is dedicated to the Public Domain.
  http://creativecommons.org/publicdomain/zero/1.0/ */
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
+/* import-globals-from ../../../shared/test/telemetry-test-helpers.js */
 /* import-globals-from ../../test/head.js */
 "use strict";
 

devtools/client/inspector/shared/highlighters-overlay.js

@@ -258,16 +258,18 @@ class HighlightersOverlay {
    *
    * @param  {NodeFront} node
    *         The NodeFront of the flexbox container element to highlight.
-   * @param  {Object} options
+   * @param. {String} trigger
-   *         Object used for passing options to the flexbox highlighter.
+   *         String name matching "layout", "markup" or "rule" to indicate where the
+   *         flexbox highlighter was toggled on from. "layout" represents the layout view.
+   *         "markup" represents the markup view. "rule" represents the rule view.
    */
-  async toggleFlexboxHighlighter(node, options = {}) {
+  async toggleFlexboxHighlighter(node, trigger) {
     if (node == this.flexboxHighlighterShown) {
       await this.hideFlexboxHighlighter(node);
       return;
     }
 
-    await this.showFlexboxHighlighter(node, options);
+    await this.showFlexboxHighlighter(node, {}, trigger);
   }
 
   /**
@@ -277,8 +279,12 @@ class HighlightersOverlay {
    *         The NodeFront of the flexbox container element to highlight.
    * @param  {Object} options
    *         Object used for passing options to the flexbox highlighter.
+   * @param. {String} trigger
+   *         String name matching "layout", "markup" or "rule" to indicate where the
+   *         flexbox highlighter was toggled on from. "layout" represents the layout view.
+   *         "markup" represents the markup view. "rule" represents the rule view.
    */
-  async showFlexboxHighlighter(node, options) {
+  async showFlexboxHighlighter(node, options, trigger) {
     const highlighter = await this._getHighlighter("FlexboxHighlighter");
     if (!highlighter) {
       return;
@@ -293,6 +299,17 @@ class HighlightersOverlay {
 
     this._toggleRuleViewIcon(node, true, ".ruleview-flex");
 
+    this.telemetry.toolOpened("flexbox_highlighter", this.inspector.toolbox.sessionId,
+      this);
+
+    if (trigger === "layout") {
+      this.telemetry.scalarAdd("devtools.layout.flexboxhighlighter.opened", 1);
+    } else if (trigger === "markup") {
+      this.telemetry.scalarAdd("devtools.markup.flexboxhighlighter.opened", 1);
+    } else if (trigger === "rule") {
+      this.telemetry.scalarAdd("devtools.rules.flexboxhighlighter.opened", 1);
+    }
+
     try {
       // Save flexbox highlighter state.
       const { url } = this.inspector.target;
@@ -319,6 +336,9 @@ class HighlightersOverlay {
       return;
     }
 
+    this.telemetry.toolClosed("flexbox_highlighter", this.inspector.toolbox.sessionId,
+      this);
+
     this._toggleRuleViewIcon(node, false, ".ruleview-flex");
 
     await this.highlighters.FlexboxHighlighter.hide();
@@ -407,10 +427,10 @@ class HighlightersOverlay {
    *
    * @param  {NodeFront} node
    *         The NodeFront of the grid container element to highlight.
-   * @param. {String|null} trigger
+   * @param. {String} trigger
-   *         String name matching "grid" or "rule" to indicate where the
+   *         String name matching "grid", "markup" or "rule" to indicate where the
-   *         grid highlighter was toggled on from. "grid" represents the grid view
+   *         grid highlighter was toggled on from. "grid" represents the grid view.
-   *         "rule" represents the rule view.
+   *         "markup" represents the markup view. "rule" represents the rule view.
    */
   async toggleGridHighlighter(node, trigger) {
     if (this.gridHighlighters.has(node)) {
@@ -428,10 +448,10 @@ class HighlightersOverlay {
    *         The NodeFront of the grid container element to highlight.
    * @param  {Object} options
    *         Object used for passing options to the grid highlighter.
-   * @param. {String|null} trigger
+   * @param. {String} trigger
-   *         String name matching "grid" or "rule" to indicate where the
+   *         String name matching "grid", "markup" or "rule" to indicate where the
-   *         grid highlighter was toggled on from. "grid" represents the grid view
+   *         grid highlighter was toggled on from. "grid" represents the grid view.
-   *         "rule" represents the rule view.
+   *         "markup" represents the markup view. "rule" represents the rule view.
    */
   async showGridHighlighter(node, options, trigger) {
     // When the grid highlighter has the given node, it is probably called with new
@@ -464,9 +484,11 @@ class HighlightersOverlay {
 
     this._toggleRuleViewIcon(node, true, ".ruleview-grid");
 
-    if (trigger == "grid") {
+    if (trigger === "grid") {
       this.telemetry.scalarAdd("devtools.grid.gridinspector.opened", 1);
-    } else if (trigger == "rule") {
+    } else if (trigger === "markup") {
+      this.telemetry.scalarAdd("devtools.markup.gridinspector.opened", 1);
+    } else if (trigger === "rule") {
       this.telemetry.scalarAdd("devtools.rules.gridinspector.opened", 1);
     }
 
@@ -968,7 +990,7 @@ class HighlightersOverlay {
 
     if (this._isRuleViewDisplayFlex(event.target)) {
       event.stopPropagation();
-      this.toggleFlexboxHighlighter(this.inspector.selection.nodeFront);
+      this.toggleFlexboxHighlighter(this.inspector.selection.nodeFront, "rule");
     }
 
     if (this._isRuleViewShapeSwatch(event.target)) {

devtools/client/shared/telemetry.js

@@ -732,16 +732,14 @@ function getChartsFromToolId(id) {
       timerHist = `DEVTOOLS_${id}_TIME_ACTIVE_SECONDS`;
       countHist = `DEVTOOLS_${id}_OPENED_COUNT`;
       break;
+    case "FLEXBOX_HIGHLIGHTER":
+      timerHist = `DEVTOOLS_${id}_TIME_ACTIVE_SECONDS`;
+      break;
     default:
       timerHist = `DEVTOOLS_CUSTOM_TIME_ACTIVE_SECONDS`;
       countHist = `DEVTOOLS_CUSTOM_OPENED_COUNT`;
   }
 
-  if (!timerHist || (!countHist && !countScalar)) {
-    throw new Error(`getChartsFromToolId cannot be called without a timer ` +
-                    `histogram and either a count histogram or count scalar.`);
-  }
-
   return {
     useTimedEvent: useTimedEvent,
     timerHist: timerHist,

devtools/client/shared/test/browser.ini

@@ -77,7 +77,9 @@ support-files =
 [browser_cubic-bezier-06.js]
 [browser_cubic-bezier-07.js]
 [browser_dbg_addon-console.js]
-skip-if = (e10s && debug || os == 'win' || verify)
+# To be removed or updated in bug 1497264
+# previously was: (e10s && debug || os == 'win' || verify)
+skip-if = true 
 tags = addons
 [browser_dbg_debugger-statement.js]
 skip-if = e10s && debug
@@ -245,7 +247,9 @@ skip-if = !e10s || os == "win" # RDM only works for remote tabs, Win: bug 140419
 skip-if = verify
 [browser_theme_switching.js]
 [browser_dbg_listaddons.js]
-skip-if = e10s && debug
+# To be removed or updated in bug 1497264
+# previously was: e10s && debug
+skip-if = true
 tags = addons
 [browser_dbg_listtabs-01.js]
 [browser_dbg_listtabs-02.js]

docshell/base/nsAboutRedirector.cpp

@@ -7,6 +7,7 @@
 #include "nsAboutRedirector.h"
 #include "nsNetUtil.h"
 #include "nsAboutProtocolUtils.h"
+#include "nsBaseChannel.h"
 #include "mozilla/ArrayUtils.h"
 #include "nsIProtocolHandler.h"
 
@@ -27,6 +28,36 @@ struct RedirEntry
   uint32_t flags;
 };
 
+class CrashChannel final : public nsBaseChannel
+{
+public:
+  explicit CrashChannel(nsIURI* aURI)
+  {
+    SetURI(aURI);
+  }
+
+  nsresult OpenContentStream(bool async, nsIInputStream **stream,
+                             nsIChannel** channel) override
+  {
+    nsAutoCString spec;
+    mURI->GetSpec(spec);
+
+    if (spec.EqualsASCII("about:crashparent") && XRE_IsParentProcess()) {
+      MOZ_CRASH("Crash via about:crashparent");
+    }
+
+    if (spec.EqualsASCII("about:crashcontent") && XRE_IsContentProcess()) {
+      MOZ_CRASH("Crash via about:crashcontent");
+    }
+
+    NS_WARNING("Unhandled about:crash* URI or wrong process");
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+protected:
+  virtual ~CrashChannel() = default;
+};
+
 /*
   Entries which do not have URI_SAFE_FOR_UNTRUSTED_CONTENT will run with chrome
   privileges. This is potentially dangerous. Please use
@@ -145,12 +176,10 @@ static const RedirEntry kRedirMap[] = {
   },
   {
     "crashparent", "about:blank",
-    nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
     nsIAboutModule::HIDE_FROM_ABOUTABOUT
   },
   {
     "crashcontent", "about:blank",
-    nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
     nsIAboutModule::HIDE_FROM_ABOUTABOUT |
     nsIAboutModule::URI_CAN_LOAD_IN_CHILD |
     nsIAboutModule::URI_MUST_LOAD_IN_CHILD
@@ -174,12 +203,10 @@ nsAboutRedirector::NewChannel(nsIURI* aURI,
   nsCOMPtr<nsIIOService> ioService = do_GetIOService(&rv);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (XRE_IsParentProcess() && path.EqualsASCII("crashparent")) {
+  if (path.EqualsASCII("crashparent") || path.EqualsASCII("crashcontent")) {
-    MOZ_CRASH("Crash via about:crashparent");
+    nsCOMPtr<nsIChannel> channel = new CrashChannel(aURI);
-  }
+    channel.forget(aResult);
-
+    return NS_OK;
-  if (XRE_IsContentProcess() && path.EqualsASCII("crashcontent")) {
-    MOZ_CRASH("Crash via about:crashcontent");
   }
 
 #ifdef ABOUT_CONFIG_BLOCKED_GV

docshell/test/mochitest/mochitest.ini

@@ -115,3 +115,4 @@ support-files = file_framedhistoryframes.html
 [test_pushState_after_document_open.html]
 [test_windowedhistoryframes.html]
 [test_triggeringprincipal_location_seturi.html]
+[test_bug1507702.html]

docshell/test/mochitest/test_bug1507702.html

@@ -0,0 +1,57 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1507702
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1507702</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <link rel="icon" href="about:crashparent"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1507702">Mozilla Bug 1507702</a>
+<img src="about:crashparent">
+<img src="about:crashcontent">
+<iframe src="about:crashparent"></iframe>
+<iframe src="about:crashcontent"></iframe>
+<script>
+  let urls = ["about:crashparent", "about:crashcontent"];
+  async function testFetch() {
+    const url = urls.shift();
+    if (!url) {
+      return Promise.resolve();
+    }
+
+    let threw;
+    try {
+      await fetch(url);
+      threw = false;
+    } catch (e) {
+      threw = true;
+    };
+
+    ok(threw === true, "fetch should reject");
+    return testFetch();
+  }
+
+  document.body.onload = async () => {
+    for (const url of ["about:crashparent", "about:crashcontent"]) {
+      SimpleTest.doesThrow(() => {
+        top.location.href = url;
+      }, "navigation should throw");
+
+      SimpleTest.doesThrow(() => {
+        location.href = url;
+      }, "navigation should throw");
+    }
+
+    await testFetch();
+    SimpleTest.finish();
+  };
+
+  SimpleTest.waitForExplicitFinish();
+</script>
+</body>
+</html>

dom/asmjscache/AsmJSCache.cpp

@@ -792,7 +792,9 @@ ParentRunnable::ReadMetadata()
 
   nsresult rv =
     qm->EnsureOriginIsInitialized(quota::PERSISTENCE_TYPE_TEMPORARY, mSuffix,
-                                  mGroup, mOrigin, getter_AddRefs(mDirectory));
+                                  mGroup, mOrigin,
+                                  /* aCreateIfNotExists */ true,
+                                  getter_AddRefs(mDirectory));
   if (NS_WARN_IF(NS_FAILED(rv))) {
     mResult = JS::AsmJSCache_StorageInitFailure;
     return rv;

dom/base/ChromeUtils.cpp

@@ -619,10 +619,7 @@ ChromeUtils::IsOriginAttributesEqual(dom::GlobalObject& aGlobal,
 ChromeUtils::IsOriginAttributesEqual(const dom::OriginAttributesDictionary& aA,
                                      const dom::OriginAttributesDictionary& aB)
 {
-  return aA.mAppId == aB.mAppId &&
+  return aA == aB;
-         aA.mInIsolatedMozBrowser == aB.mInIsolatedMozBrowser &&
-         aA.mUserContextId == aB.mUserContextId &&
-         aA.mPrivateBrowsingId == aB.mPrivateBrowsingId;
 }
 
 #ifdef NIGHTLY_BUILD

dom/base/nsGlobalWindowInner.cpp

@@ -23,6 +23,8 @@
 #include "mozilla/dom/DOMPrefs.h"
 #include "mozilla/dom/EventTarget.h"
 #include "mozilla/dom/LocalStorage.h"
+#include "mozilla/dom/LocalStorageCommon.h"
+#include "mozilla/dom/LSObject.h"
 #include "mozilla/dom/PartitionedLocalStorage.h"
 #include "mozilla/dom/Storage.h"
 #include "mozilla/dom/IdleRequest.h"
@@ -4908,32 +4910,38 @@ nsGlobalWindowInner::GetLocalStorage(ErrorResult& aError)
   if (access != nsContentUtils::StorageAccess::ePartitionedOrDeny &&
       (!mLocalStorage ||
         mLocalStorage->Type() == Storage::ePartitionedLocalStorage)) {
-    nsresult rv;
+    RefPtr<Storage> storage;
-    nsCOMPtr<nsIDOMStorageManager> storageManager =
-      do_GetService("@mozilla.org/dom/localStorage-manager;1", &rv);
-    if (NS_FAILED(rv)) {
-      aError.Throw(rv);
-      return nullptr;
-    }
 
-    nsString documentURI;
+    if (NextGenLocalStorageEnabled()) {
-    if (mDoc) {
+      aError = LSObject::CreateForWindow(this, getter_AddRefs(storage));
-      aError = mDoc->GetDocumentURI(documentURI);
+    } else {
-      if (NS_WARN_IF(aError.Failed())) {
+      nsresult rv;
+      nsCOMPtr<nsIDOMStorageManager> storageManager =
+        do_GetService("@mozilla.org/dom/localStorage-manager;1", &rv);
+      if (NS_FAILED(rv)) {
+        aError.Throw(rv);
         return nullptr;
       }
+
+      nsString documentURI;
+      if (mDoc) {
+        aError = mDoc->GetDocumentURI(documentURI);
+        if (NS_WARN_IF(aError.Failed())) {
+          return nullptr;
+        }
+      }
+
+      nsIPrincipal *principal = GetPrincipal();
+      if (!principal) {
+        aError.Throw(NS_ERROR_DOM_SECURITY_ERR);
+        return nullptr;
+      }
+
+      aError = storageManager->CreateStorage(this, principal, documentURI,
+                                             IsPrivateBrowsing(),
+                                             getter_AddRefs(storage));
     }
 
-    nsIPrincipal *principal = GetPrincipal();
-    if (!principal) {
-      aError.Throw(NS_ERROR_DOM_SECURITY_ERR);
-      return nullptr;
-    }
-
-    RefPtr<Storage> storage;
-    aError = storageManager->CreateStorage(this, principal, documentURI,
-                                           IsPrivateBrowsing(),
-                                           getter_AddRefs(storage));
     if (aError.Failed()) {
       return nullptr;
     }
@@ -5809,7 +5817,8 @@ nsGlobalWindowInner::ObserveStorageNotification(StorageEvent* aEvent,
     MOZ_DIAGNOSTIC_ASSERT(StorageUtils::PrincipalsEqual(aEvent->GetPrincipal(),
                                                         principal));
 
-    fireMozStorageChanged = mLocalStorage == aEvent->GetStorageArea();
+    fireMozStorageChanged =
+       mLocalStorage && mLocalStorage == aEvent->GetStorageArea();
 
     if (fireMozStorageChanged) {
       eventType.AssignLiteral("MozLocalStorageChanged");
@@ -5821,7 +5830,7 @@ nsGlobalWindowInner::ObserveStorageNotification(StorageEvent* aEvent,
   IgnoredErrorResult error;
   RefPtr<StorageEvent> clonedEvent =
     CloneStorageEvent(eventType, aEvent, error);
-  if (error.Failed()) {
+  if (error.Failed() || !clonedEvent) {
     return;
   }
 
@@ -5856,16 +5865,18 @@ nsGlobalWindowInner::CloneStorageEvent(const nsAString& aType,
   // If null, this is a localStorage event received by IPC.
   if (!storageArea) {
     storage = GetLocalStorage(aRv);
-    if (aRv.Failed() || !storage) {
+    if (!NextGenLocalStorageEnabled()) {
-      return nullptr;
+      if (aRv.Failed() || !storage) {
-    }
+        return nullptr;
+      }
 
-    if (storage->Type() == Storage::eLocalStorage) {
+      if (storage->Type() == Storage::eLocalStorage) {
-      RefPtr<LocalStorage> localStorage =
+        RefPtr<LocalStorage> localStorage =
-        static_cast<LocalStorage*>(storage.get());
+          static_cast<LocalStorage*>(storage.get());
 
-      // We must apply the current change to the 'local' localStorage.
+        // We must apply the current change to the 'local' localStorage.
-      localStorage->ApplyEvent(aEvent);
+        localStorage->ApplyEvent(aEvent);
+      }
     }
   } else if (storageArea->Type() == Storage::eSessionStorage) {
     storage = GetSessionStorage(aRv);
@@ -6790,6 +6801,13 @@ nsGlobalWindowInner::EventListenerAdded(nsAtom* aType)
     ErrorResult rv;
     GetLocalStorage(rv);
     rv.SuppressException();
+
+    if (NextGenLocalStorageEnabled() &&
+        mLocalStorage && mLocalStorage->Type() == Storage::eLocalStorage) {
+      auto object = static_cast<LSObject*>(mLocalStorage.get());
+
+      Unused << NS_WARN_IF(NS_FAILED(object->EnsureObserver()));
+    }
   }
 }
 
@@ -6803,6 +6821,20 @@ nsGlobalWindowInner::EventListenerRemoved(nsAtom* aType)
     MOZ_ASSERT(mBeforeUnloadListenerCount >= 0);
     mTabChild->BeforeUnloadRemoved();
   }
+
+  if (aType == nsGkAtoms::onstorage) {
+    if (NextGenLocalStorageEnabled() &&
+        mLocalStorage &&
+        mLocalStorage->Type() == Storage::eLocalStorage &&
+        // The remove event is fired even if this isn't the last listener, so
+        // only remove if there are no other listeners left.
+        mListenerManager &&
+        !mListenerManager->HasListenersFor(nsGkAtoms::onstorage)) {
+      auto object = static_cast<LSObject*>(mLocalStorage.get());
+
+      object->DropObserver();
+    }
+  }
 }
 
 void
@@ -7964,6 +7996,14 @@ nsGlobalWindowInner::StorageAccessGranted()
 
     MOZ_ASSERT(mLocalStorage &&
                mLocalStorage->Type() == Storage::eLocalStorage);
+
+    if (NextGenLocalStorageEnabled() &&
+        mListenerManager &&
+        mListenerManager->HasListenersFor(nsGkAtoms::onstorage)) {
+      auto object = static_cast<LSObject*>(mLocalStorage.get());
+
+      object->EnsureObserver();
+    }
   }
 }
 

dom/base/nsGlobalWindowOuter.cpp

@@ -27,6 +27,7 @@
 #include "mozilla/dom/ContentFrameMessageManager.h"
 #include "mozilla/dom/EventTarget.h"
 #include "mozilla/dom/LocalStorage.h"
+#include "mozilla/dom/LSObject.h"
 #include "mozilla/dom/Storage.h"
 #include "mozilla/dom/IdleRequest.h"
 #include "mozilla/dom/Performance.h"

dom/base/test/mochitest.ini

@@ -632,7 +632,7 @@ subsuite = clipboard
 skip-if = toolkit == 'android' #bug 904183
 [test_copypaste.xhtml]
 subsuite = clipboard
-skip-if = toolkit == 'android' #bug 904183
+skip-if = toolkit == 'android' && !e10s #bug 904183
 [test_createHTMLDocument.html]
 [test_data_uri.html]
 skip-if = verify

dom/bindings/BindingDeclarations.h

@@ -163,6 +163,11 @@ public:
     return mImpl == aOther.mImpl;
   }
 
+  bool operator!=(const Optional_base<T, InternalType>& aOther) const
+  {
+    return mImpl != aOther.mImpl;
+  }
+
   template<typename T1, typename T2>
   explicit Optional_base(const T1& aValue1, const T2& aValue2)
   {

dom/bindings/Codegen.py

@@ -12996,6 +12996,30 @@ class CGDictionary(CGThing):
                       "aOther")],
             body=body.define())
 
+    def canHaveEqualsOperator(self):
+        return all(m.type.isString() or m.type.isPrimitive() for (m,_) in
+                   self.memberInfo)
+
+    def equalsOperator(self):
+        body = CGList([])
+
+        for m, _ in self.memberInfo:
+            memberName = self.makeMemberName(m.identifier.name)
+            memberTest = CGGeneric(fill(
+                """
+                if (${memberName} != aOther.${memberName}) {
+                    return false;
+                }
+                """,
+                memberName=memberName))
+            body.append(memberTest)
+        body.append(CGGeneric("return true;\n"))
+        return ClassMethod(
+            "operator==", "bool",
+            [Argument("const %s&" % self.makeClassName(self.dictionary),
+                      "aOther")
+            ], const=True, body=body.define())
+
     def getStructs(self):
         d = self.dictionary
         selfName = self.makeClassName(d)
@@ -13076,6 +13100,9 @@ class CGDictionary(CGThing):
         else:
             disallowCopyConstruction = True
 
+        if self.canHaveEqualsOperator():
+            methods.append(self.equalsOperator())
+
         struct = CGClass(selfName,
                          bases=[ClassBase(self.base())],
                          members=members,

dom/browser-element/mochitest/mochitest.ini

@@ -107,7 +107,7 @@ support-files =
 [test_browserElement_inproc_CookiesNotThirdParty.html]
 [test_browserElement_inproc_CopyPaste.html]
 subsuite = clipboard
-skip-if = (os == "android") # Disabled on Android, see bug 1230421
+skip-if = (os == "android" && !e10s) # Disabled on Android, see bug 1230421
 [test_browserElement_inproc_DataURI.html]
 [test_browserElement_inproc_ExposableURI.html]
 [test_browserElement_inproc_FirstPaint.html]

dom/cache/Context.cpp

@@ -435,6 +435,7 @@ Context::QuotaInitRunnable::Run()
                                                   mQuotaInfo.mSuffix,
                                                   mQuotaInfo.mGroup,
                                                   mQuotaInfo.mOrigin,
+                                                  /* aCreateIfNotExists */ true,
                                                   getter_AddRefs(mQuotaInfo.mDir));
       if (NS_FAILED(rv)) {
         resolver->Resolve(rv);

dom/cache/FileUtils.cpp

@@ -294,7 +294,7 @@ BodyMaybeUpdatePaddingSize(const QuotaInfo& aQuotaInfo, nsIFile* aBaseDir,
   int64_t fileSize = 0;
   RefPtr<QuotaObject> quotaObject =
     quotaManager->GetQuotaObject(PERSISTENCE_TYPE_DEFAULT, aQuotaInfo.mGroup,
-                                 aQuotaInfo.mOrigin, bodyFile, &fileSize);
+                                 aQuotaInfo.mOrigin, bodyFile, -1, &fileSize);
   MOZ_DIAGNOSTIC_ASSERT(quotaObject);
   MOZ_DIAGNOSTIC_ASSERT(fileSize >= 0);
   // XXXtt: bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1422815

dom/file/ipc/IPCBlobInputStreamThread.cpp

@@ -247,5 +247,22 @@ IPCBlobInputStreamThread::DelayedDispatch(already_AddRefed<nsIRunnable>, uint32_
   return NS_ERROR_NOT_IMPLEMENTED;
 }
 
+bool
+IsOnDOMFileThread()
+{
+  mozilla::StaticMutexAutoLock lock(gIPCBlobThreadMutex);
+
+  MOZ_ASSERT(!gShutdownHasStarted);
+  MOZ_ASSERT(gIPCBlobThread);
+
+  return gIPCBlobThread->IsOnCurrentThreadInfallible();
+}
+
+void
+AssertIsOnDOMFileThread()
+{
+  MOZ_ASSERT(IsOnDOMFileThread());
+}
+
 } // dom namespace
 } // mozilla namespace

dom/file/ipc/IPCBlobInputStreamThread.h

@@ -54,6 +54,12 @@ private:
   nsTArray<RefPtr<IPCBlobInputStreamChild>> mPendingActors;
 };
 
+bool
+IsOnDOMFileThread();
+
+void
+AssertIsOnDOMFileThread();
+
 } // dom namespace
 } // mozilla namespace
 

dom/indexedDB/ActorsParent.cpp

@@ -18419,11 +18419,13 @@ Maintenance::DirectoryWork()
         // Idle maintenance may occur before origin is initailized.
         // Ensure origin is initialized first. It will initialize all origins
         // for temporary storage including IDB origins.
-        rv = quotaManager->EnsureOriginIsInitialized(persistenceType,
+        rv = quotaManager->EnsureOriginIsInitialized(
-                                                     suffix,
+                                                  persistenceType,
-                                                     group,
+                                                  suffix,
-                                                     origin,
+                                                  group,
-                                                     getter_AddRefs(directory));
+                                                  origin,
+                                                  /* aCreateIfNotExists */ true,
+                                                  getter_AddRefs(directory));
 
         if (NS_WARN_IF(NS_FAILED(rv))) {
           return rv;
@@ -21319,6 +21321,7 @@ OpenDatabaseOp::DoDatabaseWork()
                                             mSuffix,
                                             mGroup,
                                             mOrigin,
+                                            /* aCreateIfNotExists */ true,
                                             getter_AddRefs(dbDirectory));
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;

dom/interfaces/storage/nsIDOMStorageManager.idl

@@ -49,6 +49,11 @@ interface nsIDOMStorageManager : nsISupports
                         in AString aDocumentURI,
                         [optional] in bool aPrivate);
   /**
+   * DEPRECATED.  The only good reason to use this was if you were writing a
+   * test and wanted to hackily determine if a preload happened.  That's now
+   * covered by `nsILocalStorageManager.isPreloaded` and you should use that if
+   * that's what you want.  If LSNG is in use, this will throw.
+   *
    * Returns instance of DOM storage object for given principal.
    * If there is no storage managed for the scope, then null is returned and
    * no object is created.  Otherwise, an object (new) for the existing storage

dom/ipc/ContentChild.cpp

@@ -41,6 +41,7 @@
 #include "mozilla/dom/FileCreatorHelper.h"
 #include "mozilla/dom/GetFilesHelper.h"
 #include "mozilla/dom/IPCBlobUtils.h"
+#include "mozilla/dom/LSObject.h"
 #include "mozilla/dom/MemoryReportRequest.h"
 #include "mozilla/dom/PLoginReputationChild.h"
 #include "mozilla/dom/PushNotifier.h"
@@ -3811,15 +3812,21 @@ ContentChild::GetSpecificMessageEventTarget(const Message& aMsg)
   }
 }
 
-#ifdef NIGHTLY_BUILD
 void
 ContentChild::OnChannelReceivedMessage(const Message& aMsg)
 {
+  if (aMsg.is_sync()) {
+    LSObject::CancelSyncLoop();
+  }
+
+#ifdef NIGHTLY_BUILD
   if (nsContentUtils::IsMessageInputEvent(aMsg)) {
     mPendingInputEvents++;
   }
+#endif
 }
 
+#ifdef NIGHTLY_BUILD
 PContentChild::Result
 ContentChild::OnMessageReceived(const Message& aMsg)
 {

dom/ipc/ContentChild.h

@@ -768,10 +768,10 @@ private:
   virtual already_AddRefed<nsIEventTarget>
   GetSpecificMessageEventTarget(const Message& aMsg) override;
 
-#ifdef NIGHTLY_BUILD
   virtual void
   OnChannelReceivedMessage(const Message& aMsg) override;
 
+#ifdef NIGHTLY_BUILD
   virtual PContentChild::Result
   OnMessageReceived(const Message& aMsg) override;
 

dom/ipc/ContentParent.cpp

@@ -49,6 +49,7 @@
 #include "mozilla/dom/ExternalHelperAppParent.h"
 #include "mozilla/dom/GetFilesHelper.h"
 #include "mozilla/dom/GeolocationBinding.h"
+#include "mozilla/dom/LocalStorageCommon.h"
 #include "mozilla/dom/MemoryReportRequest.h"
 #include "mozilla/dom/Notification.h"
 #include "mozilla/dom/PContentBridgeParent.h"
@@ -141,6 +142,7 @@
 #include "nsIGfxInfo.h"
 #include "nsIIdleService.h"
 #include "nsIInterfaceRequestorUtils.h"
+#include "nsILocalStorageManager.h"
 #include "nsIMemoryInfoDumper.h"
 #include "nsIMemoryReporter.h"
 #include "nsIMozBrowserFrame.h"
@@ -5707,6 +5709,24 @@ ContentParent::AboutToLoadHttpFtpWyciwygDocumentForChild(nsIChannel* aChannel)
     UpdateCookieStatus(aChannel);
   }
 
+  if (!NextGenLocalStorageEnabled()) {
+    return NS_OK;
+  }
+
+  if (principal->GetIsCodebasePrincipal()) {
+    nsCOMPtr<nsILocalStorageManager> lsm =
+      do_GetService("@mozilla.org/dom/localStorage-manager;1");
+    if (NS_WARN_IF(!lsm)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    nsCOMPtr<nsISupports> dummy;
+    rv = lsm->Preload(principal, nullptr, getter_AddRefs(dummy));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  }
+
   return NS_OK;
 }
 

dom/localstorage/ActorsChild.cpp

@@ -0,0 +1,336 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ActorsChild.h"
+
+#include "LocalStorageCommon.h"
+#include "LSDatabase.h"
+#include "LSObject.h"
+#include "LSObserver.h"
+#include "LSSnapshot.h"
+
+namespace mozilla {
+namespace dom {
+
+/*******************************************************************************
+ * LSDatabaseChild
+ ******************************************************************************/
+
+LSDatabaseChild::LSDatabaseChild(LSDatabase* aDatabase)
+  : mDatabase(aDatabase)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aDatabase);
+
+  MOZ_COUNT_CTOR(LSDatabaseChild);
+}
+
+LSDatabaseChild::~LSDatabaseChild()
+{
+  AssertIsOnOwningThread();
+
+  MOZ_COUNT_DTOR(LSDatabaseChild);
+}
+
+void
+LSDatabaseChild::SendDeleteMeInternal()
+{
+  AssertIsOnOwningThread();
+
+  if (mDatabase) {
+    mDatabase->ClearActor();
+    mDatabase = nullptr;
+
+    MOZ_ALWAYS_TRUE(PBackgroundLSDatabaseChild::SendDeleteMe());
+  }
+}
+
+void
+LSDatabaseChild::ActorDestroy(ActorDestroyReason aWhy)
+{
+  AssertIsOnOwningThread();
+
+  if (mDatabase) {
+    mDatabase->ClearActor();
+#ifdef DEBUG
+    mDatabase = nullptr;
+#endif
+  }
+}
+
+mozilla::ipc::IPCResult
+LSDatabaseChild::RecvRequestAllowToClose()
+{
+  AssertIsOnOwningThread();
+
+  if (mDatabase) {
+    mDatabase->RequestAllowToClose();
+
+    // TODO: A new datastore will be prepared at first LocalStorage API
+    //       synchronous call. It would be better to start preparing a new
+    //       datastore right here, but asynchronously.
+    //       However, we probably shouldn't do that if we are shutting down.
+  }
+
+  return IPC_OK();
+}
+
+PBackgroundLSSnapshotChild*
+LSDatabaseChild::AllocPBackgroundLSSnapshotChild(const nsString& aDocumentURI,
+                                                 const bool& aIncreasePeakUsage,
+                                                 const int64_t& aRequestedSize,
+                                                 const int64_t& aMinSize,
+                                                 LSSnapshotInitInfo* aInitInfo)
+{
+  MOZ_CRASH("PBackgroundLSSnapshotChild actor should be manually constructed!");
+}
+
+bool
+LSDatabaseChild::DeallocPBackgroundLSSnapshotChild(
+                                             PBackgroundLSSnapshotChild* aActor)
+{
+  MOZ_ASSERT(aActor);
+
+  delete aActor;
+  return true;
+}
+
+/*******************************************************************************
+ * LSObserverChild
+ ******************************************************************************/
+
+LSObserverChild::LSObserverChild(LSObserver* aObserver)
+  : mObserver(aObserver)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObserver);
+
+  MOZ_COUNT_CTOR(LSObserverChild);
+}
+
+LSObserverChild::~LSObserverChild()
+{
+  AssertIsOnOwningThread();
+
+  MOZ_COUNT_DTOR(LSObserverChild);
+}
+
+void
+LSObserverChild::SendDeleteMeInternal()
+{
+  AssertIsOnOwningThread();
+
+  if (mObserver) {
+    mObserver->ClearActor();
+    mObserver = nullptr;
+
+    MOZ_ALWAYS_TRUE(PBackgroundLSObserverChild::SendDeleteMe());
+  }
+}
+
+void
+LSObserverChild::ActorDestroy(ActorDestroyReason aWhy)
+{
+  AssertIsOnOwningThread();
+
+  if (mObserver) {
+    mObserver->ClearActor();
+#ifdef DEBUG
+    mObserver = nullptr;
+#endif
+  }
+}
+
+mozilla::ipc::IPCResult
+LSObserverChild::RecvObserve(const PrincipalInfo& aPrincipalInfo,
+                             const uint32_t& aPrivateBrowsingId,
+                             const nsString& aDocumentURI,
+                             const nsString& aKey,
+                             const nsString& aOldValue,
+                             const nsString& aNewValue)
+{
+  AssertIsOnOwningThread();
+
+  if (!mObserver) {
+    return IPC_OK();
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsIPrincipal> principal =
+    PrincipalInfoToPrincipal(aPrincipalInfo, &rv);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+
+  Storage::NotifyChange(/* aStorage */ nullptr,
+                        principal,
+                        aKey,
+                        aOldValue,
+                        aNewValue,
+                        /* aStorageType */ kLocalStorageType,
+                        aDocumentURI,
+                        /* aIsPrivate */ !!aPrivateBrowsingId,
+                        /* aImmediateDispatch */ true);
+
+  return IPC_OK();
+}
+
+/*******************************************************************************
+ * LocalStorageRequestChild
+ ******************************************************************************/
+
+LSRequestChild::LSRequestChild(LSRequestChildCallback* aCallback)
+  : mCallback(aCallback)
+  , mFinishing(false)
+{
+  AssertIsOnOwningThread();
+
+  MOZ_COUNT_CTOR(LSRequestChild);
+}
+
+LSRequestChild::~LSRequestChild()
+{
+  AssertIsOnOwningThread();
+
+  MOZ_COUNT_DTOR(LSRequestChild);
+}
+
+bool
+LSRequestChild::Finishing() const
+{
+  AssertIsOnOwningThread();
+
+  return mFinishing;
+}
+
+void
+LSRequestChild::ActorDestroy(ActorDestroyReason aWhy)
+{
+  AssertIsOnOwningThread();
+}
+
+mozilla::ipc::IPCResult
+LSRequestChild::Recv__delete__(const LSRequestResponse& aResponse)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mCallback);
+
+  mCallback->OnResponse(aResponse);
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
+LSRequestChild::RecvReady()
+{
+  AssertIsOnOwningThread();
+
+  mFinishing = true;
+
+  SendFinish();
+
+  return IPC_OK();
+}
+
+/*******************************************************************************
+ * LSSimpleRequestChild
+ ******************************************************************************/
+
+LSSimpleRequestChild::LSSimpleRequestChild(
+                                        LSSimpleRequestChildCallback* aCallback)
+  : mCallback(aCallback)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aCallback);
+
+  MOZ_COUNT_CTOR(LSSimpleRequestChild);
+}
+
+LSSimpleRequestChild::~LSSimpleRequestChild()
+{
+  AssertIsOnOwningThread();
+
+  MOZ_COUNT_DTOR(LSSimpleRequestChild);
+}
+
+void
+LSSimpleRequestChild::ActorDestroy(ActorDestroyReason aWhy)
+{
+  AssertIsOnOwningThread();
+}
+
+mozilla::ipc::IPCResult
+LSSimpleRequestChild::Recv__delete__(const LSSimpleRequestResponse& aResponse)
+{
+  AssertIsOnOwningThread();
+
+  mCallback->OnResponse(aResponse);
+
+  return IPC_OK();
+}
+
+/*******************************************************************************
+ * LSSnapshotChild
+ ******************************************************************************/
+
+LSSnapshotChild::LSSnapshotChild(LSSnapshot* aSnapshot)
+  : mSnapshot(aSnapshot)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aSnapshot);
+
+  MOZ_COUNT_CTOR(LSSnapshotChild);
+}
+
+LSSnapshotChild::~LSSnapshotChild()
+{
+  AssertIsOnOwningThread();
+
+  MOZ_COUNT_DTOR(LSSnapshotChild);
+}
+
+void
+LSSnapshotChild::SendDeleteMeInternal()
+{
+  AssertIsOnOwningThread();
+
+  if (mSnapshot) {
+    mSnapshot->ClearActor();
+    mSnapshot = nullptr;
+
+    MOZ_ALWAYS_TRUE(PBackgroundLSSnapshotChild::SendDeleteMe());
+  }
+}
+
+void
+LSSnapshotChild::ActorDestroy(ActorDestroyReason aWhy)
+{
+  AssertIsOnOwningThread();
+
+  if (mSnapshot) {
+    mSnapshot->ClearActor();
+#ifdef DEBUG
+    mSnapshot = nullptr;
+#endif
+  }
+}
+
+mozilla::ipc::IPCResult
+LSSnapshotChild::RecvMarkDirty()
+{
+  AssertIsOnOwningThread();
+
+  if (!mSnapshot) {
+    return IPC_OK();
+  }
+
+  mSnapshot->MarkDirty();
+
+  return IPC_OK();
+}
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/ActorsChild.h

@@ -0,0 +1,313 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_ActorsChild_h
+#define mozilla_dom_localstorage_ActorsChild_h
+
+#include "mozilla/dom/PBackgroundLSDatabaseChild.h"
+#include "mozilla/dom/PBackgroundLSObserverChild.h"
+#include "mozilla/dom/PBackgroundLSRequestChild.h"
+#include "mozilla/dom/PBackgroundLSSimpleRequestChild.h"
+#include "mozilla/dom/PBackgroundLSSnapshotChild.h"
+
+namespace mozilla {
+
+namespace ipc {
+
+class BackgroundChildImpl;
+
+} // namespace ipc
+
+namespace dom {
+
+class LocalStorageManager2;
+class LSDatabase;
+class LSObject;
+class LSObserver;
+class LSRequestChildCallback;
+class LSSimpleRequestChildCallback;
+class LSSnapshot;
+
+/**
+ * Minimal glue actor with standard IPC-managed new/delete existence that exists
+ * primarily to track the continued existence of the LSDatabase in the child.
+ * Most of the interesting bits happen via PBackgroundLSSnapshot.
+ *
+ * Mutual raw pointers are maintained between LSDatabase and this class that are
+ * cleared at either (expected) when the child starts the deletion process
+ * (SendDeleteMeInternal) or unexpected actor death (ActorDestroy).
+ *
+ * See `PBackgroundLSDatabase.ipdl` for more information.
+ *
+ *
+ * ## Low-Level Lifecycle ##
+ * - Created by LSObject::EnsureDatabase if it had to create a database.
+ * - Deletion begun by LSDatabase's destructor invoking SendDeleteMeInternal
+ *   which will result in the parent sending __delete__ which destroys the
+ *   actor.
+ */
+class LSDatabaseChild final
+  : public PBackgroundLSDatabaseChild
+{
+  friend class mozilla::ipc::BackgroundChildImpl;
+  friend class LSDatabase;
+  friend class LSObject;
+
+  LSDatabase* mDatabase;
+
+  NS_DECL_OWNINGTHREAD
+
+public:
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSDatabaseChild);
+  }
+
+private:
+  // Only created by LSObject.
+  explicit LSDatabaseChild(LSDatabase* aDatabase);
+
+  // Only destroyed by mozilla::ipc::BackgroundChildImpl.
+  ~LSDatabaseChild();
+
+  void
+  SendDeleteMeInternal();
+
+  // IPDL methods are only called by IPDL.
+  void
+  ActorDestroy(ActorDestroyReason aWhy) override;
+
+  mozilla::ipc::IPCResult
+  RecvRequestAllowToClose() override;
+
+  PBackgroundLSSnapshotChild*
+  AllocPBackgroundLSSnapshotChild(const nsString& aDocumentURI,
+                                  const bool& aIncreasePeakUsage,
+                                  const int64_t& aRequestedSize,
+                                  const int64_t& aMinSize,
+                                  LSSnapshotInitInfo* aInitInfo) override;
+
+  bool
+  DeallocPBackgroundLSSnapshotChild(PBackgroundLSSnapshotChild* aActor)
+                                    override;
+};
+
+/**
+ * Minimal IPC-managed (new/delete) actor that exists to receive and relay
+ * "storage" events from changes to LocalStorage that take place in other
+ * processes as their Snapshots are checkpointed to the canonical Datastore in
+ * the parent process.
+ *
+ * See `PBackgroundLSObserver.ipdl` for more info.
+ */
+class LSObserverChild final
+  : public PBackgroundLSObserverChild
+{
+  friend class mozilla::ipc::BackgroundChildImpl;
+  friend class LSObserver;
+  friend class LSObject;
+
+  LSObserver* mObserver;
+
+  NS_DECL_OWNINGTHREAD
+
+public:
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSObserverChild);
+  }
+
+private:
+  // Only created by LSObject.
+  explicit LSObserverChild(LSObserver* aObserver);
+
+  // Only destroyed by mozilla::ipc::BackgroundChildImpl.
+  ~LSObserverChild();
+
+  void
+  SendDeleteMeInternal();
+
+  // IPDL methods are only called by IPDL.
+  void
+  ActorDestroy(ActorDestroyReason aWhy) override;
+
+  mozilla::ipc::IPCResult
+  RecvObserve(const PrincipalInfo& aPrinciplaInfo,
+              const uint32_t& aPrivateBrowsingId,
+              const nsString& aDocumentURI,
+              const nsString& aKey,
+              const nsString& aOldValue,
+              const nsString& aNewValue) override;
+};
+
+/**
+ * Minimal glue IPC-managed (new/delete) actor that is used by LSObject and its
+ * RequestHelper to perform synchronous requests on top of an asynchronous
+ * protocol.
+ *
+ * Takes an `LSReuestChildCallback` to be invoked when a response is received
+ * via __delete__.
+ *
+ * See `PBackgroundLSRequest.ipdl`, `LSObject`, and `RequestHelper` for more
+ * info.
+ */
+class LSRequestChild final
+  : public PBackgroundLSRequestChild
+{
+  friend class LSObject;
+  friend class LocalStorageManager2;
+
+  RefPtr<LSRequestChildCallback> mCallback;
+
+  bool mFinishing;
+
+  NS_DECL_OWNINGTHREAD
+
+public:
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSReqeustChild);
+  }
+
+  bool
+  Finishing() const;
+
+private:
+  // Only created by LSObject.
+  explicit LSRequestChild(LSRequestChildCallback* aCallback);
+
+  // Only destroyed by mozilla::ipc::BackgroundChildImpl.
+  ~LSRequestChild();
+
+  // IPDL methods are only called by IPDL.
+  void
+  ActorDestroy(ActorDestroyReason aWhy) override;
+
+  mozilla::ipc::IPCResult
+  Recv__delete__(const LSRequestResponse& aResponse) override;
+
+  mozilla::ipc::IPCResult
+  RecvReady() override;
+};
+
+class NS_NO_VTABLE LSRequestChildCallback
+{
+public:
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+  virtual void
+  OnResponse(const LSRequestResponse& aResponse) = 0;
+
+protected:
+  virtual ~LSRequestChildCallback()
+  { }
+};
+
+/**
+ * Minimal glue IPC-managed (new/delete) actor used by `LocalStorageManager2` to
+ * issue asynchronous requests in an asynchronous fashion.
+ *
+ * Takes an `LSSimpleRequestChildCallback` to be invoked when a response is
+ * received via __delete__.
+ *
+ * See `PBackgroundLSSimpleRequest.ipdl` for more info.
+ */
+class LSSimpleRequestChild final
+  : public PBackgroundLSSimpleRequestChild
+{
+  friend class LocalStorageManager2;
+
+  RefPtr<LSSimpleRequestChildCallback> mCallback;
+
+  NS_DECL_OWNINGTHREAD
+
+public:
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSSimpleReqeustChild);
+  }
+
+private:
+  // Only created by LocalStorageManager2.
+  explicit LSSimpleRequestChild(LSSimpleRequestChildCallback* aCallback);
+
+  // Only destroyed by mozilla::ipc::BackgroundChildImpl.
+  ~LSSimpleRequestChild();
+
+  // IPDL methods are only called by IPDL.
+  void
+  ActorDestroy(ActorDestroyReason aWhy) override;
+
+  mozilla::ipc::IPCResult
+  Recv__delete__(const LSSimpleRequestResponse& aResponse) override;
+};
+
+class NS_NO_VTABLE LSSimpleRequestChildCallback
+{
+public:
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+  virtual void
+  OnResponse(const LSSimpleRequestResponse& aResponse) = 0;
+
+protected:
+  virtual ~LSSimpleRequestChildCallback()
+  { }
+};
+
+/**
+ * Minimal IPC-managed (new/delete) actor that lasts as long as its owning
+ * LSSnapshot.
+ *
+ * Mutual raw pointers are maintained between LSSnapshot and this class that are
+ * cleared at either (expected) when the child starts the deletion process
+ * (SendDeleteMeInternal) or unexpected actor death (ActorDestroy).
+ *
+ * See `PBackgroundLSSnapshot.ipdl` and `LSSnapshot` for more info.
+ */
+class LSSnapshotChild final
+  : public PBackgroundLSSnapshotChild
+{
+  friend class LSDatabase;
+  friend class LSSnapshot;
+
+  LSSnapshot* mSnapshot;
+
+  NS_DECL_OWNINGTHREAD
+
+public:
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSSnapshotChild);
+  }
+
+private:
+  // Only created by LSDatabase.
+  explicit LSSnapshotChild(LSSnapshot* aSnapshot);
+
+  // Only destroyed by LSDatabaseChild.
+  ~LSSnapshotChild();
+
+  void
+  SendDeleteMeInternal();
+
+  // IPDL methods are only called by IPDL.
+  void
+  ActorDestroy(ActorDestroyReason aWhy) override;
+
+  mozilla::ipc::IPCResult
+  RecvMarkDirty() override;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_ActorsChild_h

dom/localstorage/ActorsParent.h

@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_ActorsParent_h
+#define mozilla_dom_localstorage_ActorsParent_h
+
+namespace mozilla {
+
+namespace ipc {
+
+class PBackgroundParent;
+class PrincipalInfo;
+
+} // namespace ipc
+
+namespace dom {
+
+class LSRequestParams;
+class LSSimpleRequestParams;
+class PBackgroundLSDatabaseParent;
+class PBackgroundLSObserverParent;
+class PBackgroundLSRequestParent;
+class PBackgroundLSSimpleRequestParent;
+
+namespace quota {
+
+class Client;
+
+} // namespace quota
+
+PBackgroundLSDatabaseParent*
+AllocPBackgroundLSDatabaseParent(
+                              const mozilla::ipc::PrincipalInfo& aPrincipalInfo,
+                              const uint32_t& aPrivateBrowsingId,
+                              const uint64_t& aDatastoreId);
+
+bool
+RecvPBackgroundLSDatabaseConstructor(
+                              PBackgroundLSDatabaseParent* aActor,
+                              const mozilla::ipc::PrincipalInfo& aPrincipalInfo,
+                              const uint32_t& aPrivateBrowsingId,
+                              const uint64_t& aDatastoreId);
+
+bool
+DeallocPBackgroundLSDatabaseParent(PBackgroundLSDatabaseParent* aActor);
+
+PBackgroundLSObserverParent*
+AllocPBackgroundLSObserverParent(const uint64_t& aObserverId);
+
+bool
+RecvPBackgroundLSObserverConstructor(PBackgroundLSObserverParent* aActor,
+                                     const uint64_t& aObservereId);
+
+bool
+DeallocPBackgroundLSObserverParent(PBackgroundLSObserverParent* aActor);
+
+PBackgroundLSRequestParent*
+AllocPBackgroundLSRequestParent(
+                              mozilla::ipc::PBackgroundParent* aBackgroundActor,
+                              const LSRequestParams& aParams);
+
+bool
+RecvPBackgroundLSRequestConstructor(PBackgroundLSRequestParent* aActor,
+                                    const LSRequestParams& aParams);
+
+bool
+DeallocPBackgroundLSRequestParent(PBackgroundLSRequestParent* aActor);
+
+PBackgroundLSSimpleRequestParent*
+AllocPBackgroundLSSimpleRequestParent(const LSSimpleRequestParams& aParams);
+
+bool
+RecvPBackgroundLSSimpleRequestConstructor(
+                                       PBackgroundLSSimpleRequestParent* aActor,
+                                       const LSSimpleRequestParams& aParams);
+
+bool
+DeallocPBackgroundLSSimpleRequestParent(
+                                      PBackgroundLSSimpleRequestParent* aActor);
+
+namespace localstorage {
+
+already_AddRefed<mozilla::dom::quota::Client>
+CreateQuotaClient();
+
+} // namespace localstorage
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_ActorsParent_h

dom/localstorage/LSDatabase.cpp

@@ -0,0 +1,364 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LSDatabase.h"
+
+namespace mozilla {
+namespace dom {
+
+namespace {
+
+typedef nsDataHashtable<nsCStringHashKey, LSDatabase*> LSDatabaseHashtable;
+
+StaticAutoPtr<LSDatabaseHashtable> gLSDatabases;
+
+} // namespace
+
+LSDatabase::LSDatabase(const nsACString& aOrigin)
+  : mActor(nullptr)
+  , mSnapshot(nullptr)
+  , mOrigin(aOrigin)
+  , mAllowedToClose(false)
+  , mRequestedAllowToClose(false)
+{
+  AssertIsOnOwningThread();
+
+  if (!gLSDatabases) {
+    gLSDatabases = new LSDatabaseHashtable();
+  }
+
+  MOZ_ASSERT(!gLSDatabases->Get(mOrigin));
+  gLSDatabases->Put(mOrigin, this);
+}
+
+LSDatabase::~LSDatabase()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(!mSnapshot);
+
+  if (!mAllowedToClose) {
+    AllowToClose();
+  }
+
+  if (mActor) {
+    mActor->SendDeleteMeInternal();
+    MOZ_ASSERT(!mActor, "SendDeleteMeInternal should have cleared!");
+  }
+}
+
+// static
+LSDatabase*
+LSDatabase::Get(const nsACString& aOrigin)
+{
+  return gLSDatabases ? gLSDatabases->Get(aOrigin) : nullptr;
+}
+
+void
+LSDatabase::SetActor(LSDatabaseChild* aActor)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aActor);
+  MOZ_ASSERT(!mActor);
+
+  mActor = aActor;
+}
+
+void
+LSDatabase::RequestAllowToClose()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(!mRequestedAllowToClose);
+
+  mRequestedAllowToClose = true;
+
+  if (mSnapshot) {
+    mSnapshot->MarkDirty();
+  } else {
+    AllowToClose();
+  }
+}
+
+void
+LSDatabase::NoteFinishedSnapshot(LSSnapshot* aSnapshot)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aSnapshot == mSnapshot);
+
+  mSnapshot = nullptr;
+
+  if (mRequestedAllowToClose) {
+    AllowToClose();
+  }
+}
+
+nsresult
+LSDatabase::GetLength(LSObject* aObject,
+                      uint32_t* aResult)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  nsresult rv = EnsureSnapshot(aObject);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mSnapshot->GetLength(aResult);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::GetKey(LSObject* aObject,
+                   uint32_t aIndex,
+                   nsAString& aResult)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  nsresult rv = EnsureSnapshot(aObject);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mSnapshot->GetKey(aIndex, aResult);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::GetItem(LSObject* aObject,
+                    const nsAString& aKey,
+                    nsAString& aResult)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  nsresult rv = EnsureSnapshot(aObject);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mSnapshot->GetItem(aKey, aResult);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::GetKeys(LSObject* aObject,
+                    nsTArray<nsString>& aKeys)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  nsresult rv = EnsureSnapshot(aObject);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mSnapshot->GetKeys(aKeys);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::SetItem(LSObject* aObject,
+                    const nsAString& aKey,
+                    const nsAString& aValue,
+                    LSNotifyInfo& aNotifyInfo)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  nsresult rv = EnsureSnapshot(aObject);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mSnapshot->SetItem(aKey, aValue, aNotifyInfo);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::RemoveItem(LSObject* aObject,
+                       const nsAString& aKey,
+                       LSNotifyInfo& aNotifyInfo)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  nsresult rv = EnsureSnapshot(aObject);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mSnapshot->RemoveItem(aKey, aNotifyInfo);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::Clear(LSObject* aObject,
+                  LSNotifyInfo& aNotifyInfo)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  nsresult rv = EnsureSnapshot(aObject);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = mSnapshot->Clear(aNotifyInfo);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::BeginExplicitSnapshot(LSObject* aObject)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  if (mSnapshot) {
+    return NS_ERROR_ALREADY_INITIALIZED;
+  }
+
+  nsresult rv = EnsureSnapshot(aObject, /* aExplicit */ true);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::EndExplicitSnapshot(LSObject* aObject)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  if (!mSnapshot) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  MOZ_ASSERT(mSnapshot->Explicit());
+
+  nsresult rv = mSnapshot->End();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSDatabase::EnsureSnapshot(LSObject* aObject,
+                           bool aExplicit)
+{
+  MOZ_ASSERT(aObject);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT_IF(mSnapshot, !aExplicit);
+  MOZ_ASSERT(!mAllowedToClose);
+
+  if (mSnapshot) {
+    return NS_OK;
+  }
+
+  RefPtr<LSSnapshot> snapshot = new LSSnapshot(this);
+
+  LSSnapshotChild* actor = new LSSnapshotChild(snapshot);
+
+  LSSnapshotInitInfo initInfo;
+  bool ok =
+    mActor->SendPBackgroundLSSnapshotConstructor(actor,
+                                                 aObject->DocumentURI(),
+                                                 /* increasePeakUsage */ true,
+                                                 /* requestedSize */ 131072,
+                                                 /* minSize */ 4096,
+                                                 &initInfo);
+  if (NS_WARN_IF(!ok)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  snapshot->SetActor(actor);
+
+  // This add refs snapshot.
+  nsresult rv = snapshot->Init(initInfo, aExplicit);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // This is cleared in LSSnapshot::Run() before the snapshot is destroyed.
+  mSnapshot = snapshot;
+
+  return NS_OK;
+}
+
+void
+LSDatabase::AllowToClose()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(!mAllowedToClose);
+  MOZ_ASSERT(!mSnapshot);
+
+  mAllowedToClose = true;
+
+  if (mActor) {
+    mActor->SendAllowToClose();
+  }
+
+  MOZ_ASSERT(gLSDatabases);
+  MOZ_ASSERT(gLSDatabases->Get(mOrigin));
+  gLSDatabases->Remove(mOrigin);
+
+  if (!gLSDatabases->Count()) {
+    gLSDatabases = nullptr;
+  }
+}
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/LSDatabase.h

@@ -0,0 +1,120 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_LSDatabase_h
+#define mozilla_dom_localstorage_LSDatabase_h
+
+namespace mozilla {
+namespace dom {
+
+class LSDatabaseChild;
+class LSSnapshot;
+
+class LSDatabase final
+{
+  LSDatabaseChild* mActor;
+
+  LSSnapshot* mSnapshot;
+
+  const nsCString mOrigin;
+
+  bool mAllowedToClose;
+  bool mRequestedAllowToClose;
+
+public:
+  explicit LSDatabase(const nsACString& aOrigin);
+
+  static LSDatabase*
+  Get(const nsACString& aOrigin);
+
+  NS_INLINE_DECL_REFCOUNTING(LSDatabase)
+
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSDatabase);
+  }
+
+  void
+  SetActor(LSDatabaseChild* aActor);
+
+  void
+  ClearActor()
+  {
+    AssertIsOnOwningThread();
+    MOZ_ASSERT(mActor);
+
+    mActor = nullptr;
+  }
+
+  bool
+  IsAllowedToClose() const
+  {
+    AssertIsOnOwningThread();
+
+    return mAllowedToClose;
+  }
+
+  void
+  RequestAllowToClose();
+
+  void
+  NoteFinishedSnapshot(LSSnapshot* aSnapshot);
+
+  nsresult
+  GetLength(LSObject* aObject,
+            uint32_t* aResult);
+
+  nsresult
+  GetKey(LSObject* aObject,
+         uint32_t aIndex,
+         nsAString& aResult);
+
+  nsresult
+  GetItem(LSObject* aObject,
+          const nsAString& aKey,
+          nsAString& aResult);
+
+  nsresult
+  GetKeys(LSObject* aObject,
+          nsTArray<nsString>& aKeys);
+
+  nsresult
+  SetItem(LSObject* aObject,
+          const nsAString& aKey,
+          const nsAString& aValue,
+          LSNotifyInfo& aNotifyInfo);
+
+  nsresult
+  RemoveItem(LSObject* aObject,
+             const nsAString& aKey,
+             LSNotifyInfo& aNotifyInfo);
+
+  nsresult
+  Clear(LSObject* aObject,
+        LSNotifyInfo& aNotifyInfo);
+
+  nsresult
+  BeginExplicitSnapshot(LSObject* aObject);
+
+  nsresult
+  EndExplicitSnapshot(LSObject* aObject);
+
+private:
+  ~LSDatabase();
+
+  nsresult
+  EnsureSnapshot(LSObject* aObject,
+                 bool aExplicit = false);
+
+  void
+  AllowToClose();
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_LSDatabase_h

dom/localstorage/LSObject.h

@@ -0,0 +1,262 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_LSObject_h
+#define mozilla_dom_localstorage_LSObject_h
+
+#include "mozilla/dom/Storage.h"
+
+class nsGlobalWindowInner;
+class nsIPrincipal;
+class nsPIDOMWindowInner;
+
+namespace mozilla {
+
+class ErrorResult;
+
+namespace ipc {
+
+class PrincipalInfo;
+
+} // namespace ipc
+
+namespace dom {
+
+class LSDatabase;
+class LSObjectChild;
+class LSObserver;
+class LSRequestChild;
+class LSRequestChildCallback;
+class LSRequestParams;
+class LSRequestResponse;
+
+/**
+ * Backs the WebIDL `Storage` binding; all content LocalStorage calls are
+ * handled by this class.
+ *
+ * ## Semantics under e10s / multi-process ##
+ *
+ * A snapshot mechanism used in conjuction with stable points ensures that JS
+ * run-to-completion semantics are experienced even if the same origin is
+ * concurrently accessing LocalStorage across multiple content processes.
+ *
+ * ### Snapshot Consistency ###
+ *
+ * An LSSnapshot is created locally whenever the contents of LocalStorage are
+ * about to be read or written (including length).  This synchronously
+ * establishes a corresponding Snapshot in PBackground in the parent process.
+ * An effort is made to send as much data from the parent process as possible,
+ * so sites using a small/reasonable amount of LocalStorage data will have it
+ * sent to the content process for immediate access.  Sites with greater
+ * LocalStorage usage may only have some of the information relayed.  In that
+ * case, the parent Snapshot will ensure that it retains the exact state of the
+ * parent Datastore at the moment the Snapshot was created.
+ */
+class LSObject final
+  : public Storage
+{
+  typedef mozilla::ipc::PrincipalInfo PrincipalInfo;
+
+  friend nsGlobalWindowInner;
+
+  nsAutoPtr<PrincipalInfo> mPrincipalInfo;
+
+  RefPtr<LSDatabase> mDatabase;
+  RefPtr<LSObserver> mObserver;
+
+  uint32_t mPrivateBrowsingId;
+  nsCString mOrigin;
+  nsString mDocumentURI;
+
+  bool mInExplicitSnapshot;
+
+public:
+  /**
+   * The normal creation path invoked by nsGlobalWindowInner.
+   */
+  static nsresult
+  CreateForWindow(nsPIDOMWindowInner* aWindow,
+                  Storage** aStorage);
+
+  /**
+   * nsIDOMStorageManager creation path for use in testing logic.  Supports the
+   * system principal where CreateForWindow does not.  This is also why aPrivate
+   * exists separate from the principal; because the system principal can never
+   * be mutated to have a private browsing id even though it can be used in a
+   * window/document marked as private browsing.  That's a legacy issue that is
+   * being dealt with, but it's why it exists here.
+   */
+  static nsresult
+  CreateForPrincipal(nsPIDOMWindowInner* aWindow,
+                     nsIPrincipal* aPrincipal,
+                     const nsAString& aDocumentURI,
+                     bool aPrivate,
+                     LSObject** aObject);
+
+  /**
+   * Used for requests from the parent process to the parent process; in that
+   * case we want ActorsParent to know our event-target and this is better than
+   * trying to tunnel the pointer through IPC.
+   */
+  static already_AddRefed<nsIEventTarget>
+  GetSyncLoopEventTarget();
+
+  /**
+   * Helper invoked by ContentChild::OnChannelReceivedMessage when a sync IPC
+   * message is received.  This will be invoked on the IPC I/O thread and it's
+   * necessary to unblock the main thread when this happens to avoid the
+   * potential for browser deadlock.  This should only occur in (ugly) testing
+   * scenarios where CPOWs are in use.
+   *
+   * Cancellation will result in the underlying LSRequest being explicitly
+   * canceled, resulting in the parent sending an NS_ERROR_FAILURE result.
+   */
+  static void
+  CancelSyncLoop();
+
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSObject);
+  }
+
+  const nsString&
+  DocumentURI() const
+  {
+    return mDocumentURI;
+  }
+
+  LSRequestChild*
+  StartRequest(nsIEventTarget* aMainEventTarget,
+               const LSRequestParams& aParams,
+               LSRequestChildCallback* aCallback);
+
+  // Storage overrides.
+  StorageType
+  Type() const override;
+
+  bool
+  IsForkOf(const Storage* aStorage) const override;
+
+  int64_t
+  GetOriginQuotaUsage() const override;
+
+  uint32_t
+  GetLength(nsIPrincipal& aSubjectPrincipal,
+            ErrorResult& aError) override;
+
+  void
+  Key(uint32_t aIndex,
+      nsAString& aResult,
+      nsIPrincipal& aSubjectPrincipal,
+      ErrorResult& aError) override;
+
+  void
+  GetItem(const nsAString& aKey,
+          nsAString& aResult,
+          nsIPrincipal& aSubjectPrincipal,
+          ErrorResult& aError) override;
+
+  void
+  GetSupportedNames(nsTArray<nsString>& aNames) override;
+
+  void
+  SetItem(const nsAString& aKey,
+          const nsAString& aValue,
+          nsIPrincipal& aSubjectPrincipal,
+          ErrorResult& aError) override;
+
+  void
+  RemoveItem(const nsAString& aKey,
+             nsIPrincipal& aSubjectPrincipal,
+             ErrorResult& aError) override;
+
+  void
+  Clear(nsIPrincipal& aSubjectPrincipal,
+        ErrorResult& aError) override;
+
+  //////////////////////////////////////////////////////////////////////////////
+  // Testing Methods: See Storage.h
+  void
+  Open(nsIPrincipal& aSubjectPrincipal,
+       ErrorResult& aError) override;
+
+  void
+  Close(nsIPrincipal& aSubjectPrincipal,
+        ErrorResult& aError) override;
+
+  void
+  BeginExplicitSnapshot(nsIPrincipal& aSubjectPrincipal,
+                        ErrorResult& aError) override;
+
+  void
+  EndExplicitSnapshot(nsIPrincipal& aSubjectPrincipal,
+                      ErrorResult& aError) override;
+
+  //////////////////////////////////////////////////////////////////////////////
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(LSObject, Storage)
+
+private:
+  LSObject(nsPIDOMWindowInner* aWindow,
+           nsIPrincipal* aPrincipal);
+
+  ~LSObject();
+
+  nsresult
+  DoRequestSynchronously(const LSRequestParams& aParams,
+                         LSRequestResponse& aResponse);
+
+  nsresult
+  EnsureDatabase();
+
+  void
+  DropDatabase();
+
+  /**
+   * Invoked by nsGlobalWindowInner whenever a new "storage" event listener is
+   * added to the window in order to ensure that "storage" events are received
+   * from other processes.  (`LSObject::OnChange` directly invokes
+   * `Storage::NotifyChange` to notify in-process listeners.)
+   *
+   * If this is the first request in the process for an observer for this
+   * origin, this will trigger a RequestHelper-mediated synchronous LSRequest
+   * to prepare a new observer in the parent process and also construction of
+   * corresponding actors, which will result in the observer being fully
+   * registered in the parent process.
+   */
+  nsresult
+  EnsureObserver();
+
+  /**
+   * Invoked by nsGlobalWindowInner whenever its last "storage" event listener
+   * is removed.
+   */
+  void
+  DropObserver();
+
+  /**
+   * Internal helper method used by mutation methods that wraps the call to
+   * Storage::NotifyChange to generate same-process "storage" events.
+   */
+  void
+  OnChange(const nsAString& aKey,
+           const nsAString& aOldValue,
+           const nsAString& aNewValue);
+
+  nsresult
+  EndExplicitSnapshotInternal();
+
+  // Storage overrides.
+  void
+  LastRelease() override;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_LSObject_h

dom/localstorage/LSObserver.cpp

@@ -0,0 +1,76 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LSObserver.h"
+
+#include "mozilla/ipc/BackgroundChild.h"
+#include "mozilla/ipc/BackgroundUtils.h"
+#include "mozilla/ipc/PBackgroundChild.h"
+#include "nsContentUtils.h"
+#include "nsIScriptObjectPrincipal.h"
+
+namespace mozilla {
+namespace dom {
+
+namespace {
+
+typedef nsDataHashtable<nsCStringHashKey, LSObserver*> LSObserverHashtable;
+
+StaticAutoPtr<LSObserverHashtable> gLSObservers;
+
+} // namespace
+
+LSObserver::LSObserver(const nsACString& aOrigin)
+  : mActor(nullptr)
+  , mOrigin(aOrigin)
+{
+  AssertIsOnOwningThread();
+
+  if (!gLSObservers) {
+    gLSObservers = new LSObserverHashtable();
+  }
+
+  MOZ_ASSERT(!gLSObservers->Get(mOrigin));
+  gLSObservers->Put(mOrigin, this);
+}
+
+LSObserver::~LSObserver()
+{
+  AssertIsOnOwningThread();
+
+  if (mActor) {
+    mActor->SendDeleteMeInternal();
+    MOZ_ASSERT(!mActor, "SendDeleteMeInternal should have cleared!");
+  }
+
+  MOZ_ASSERT(gLSObservers);
+  MOZ_ASSERT(gLSObservers->Get(mOrigin));
+  gLSObservers->Remove(mOrigin);
+
+  if (!gLSObservers->Count()) {
+    gLSObservers = nullptr;
+  }
+}
+
+// static
+LSObserver*
+LSObserver::Get(const nsACString& aOrigin)
+{
+  return gLSObservers ? gLSObservers->Get(aOrigin) : nullptr;
+}
+
+void
+LSObserver::SetActor(LSObserverChild* aActor)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aActor);
+  MOZ_ASSERT(!mActor);
+
+  mActor = aActor;
+}
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/LSObserver.h

@@ -0,0 +1,74 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_LSObserver_h
+#define mozilla_dom_localstorage_LSObserver_h
+
+namespace mozilla {
+namespace dom {
+
+class LSObserverChild;
+
+/**
+ * Effectively just a refcounted life-cycle management wrapper around
+ * LSObserverChild which exists to receive "storage" event information from
+ * other processes.  (Same-process events are handled within the process, see
+ * `LSObject::OnChange`.)
+ *
+ * ## Lifecycle ##
+ * - Created by LSObject::EnsureObserver via synchronous LSRequest idiom
+ *   whenever the first window's origin adds a "storage" event.  Placed in the
+ *   gLSObservers LSObserverHashtable for subsequent LSObject's via
+ *   LSObserver::Get lookup.
+ * - The LSObserverChild directly handles "Observe" messages, shunting them
+ *   directly to Storage::NotifyChange which does all the legwork of notifying
+ *   windows about "storage" events.
+ * - Destroyed when refcount goes to zero due to all owning LSObjects being
+ *   destroyed or having their `LSObject::DropObserver` methods invoked due to
+ *   the last "storage" event listener being removed from the owning window.
+ */
+class LSObserver final
+{
+  friend class LSObject;
+
+  LSObserverChild* mActor;
+
+  const nsCString mOrigin;
+
+public:
+  explicit LSObserver(const nsACString& aOrigin);
+
+  static LSObserver*
+  Get(const nsACString& aOrigin);
+
+  NS_INLINE_DECL_REFCOUNTING(LSObserver)
+
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSDatabase);
+  }
+
+  void
+  SetActor(LSObserverChild* aActor);
+
+  void
+  ClearActor()
+  {
+    AssertIsOnOwningThread();
+    MOZ_ASSERT(mActor);
+
+    mActor = nullptr;
+  }
+
+private:
+  ~LSObserver();
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_LSObserver_h

dom/localstorage/LSSnapshot.cpp

@@ -0,0 +1,785 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LSSnapshot.h"
+
+#include "nsContentUtils.h"
+
+namespace mozilla {
+namespace dom {
+
+namespace {
+
+const uint32_t kSnapshotTimeoutMs = 20000;
+
+} // namespace
+
+LSSnapshot::LSSnapshot(LSDatabase* aDatabase)
+  : mDatabase(aDatabase)
+  , mActor(nullptr)
+  , mInitLength(0)
+  , mLength(0)
+  , mExactUsage(0)
+  , mPeakUsage(0)
+  , mLoadState(LoadState::Initial)
+  , mExplicit(false)
+  , mHasPendingStableStateCallback(false)
+  , mHasPendingTimerCallback(false)
+  , mDirty(false)
+#ifdef DEBUG
+  , mInitialized(false)
+  , mSentFinish(false)
+#endif
+{
+  AssertIsOnOwningThread();
+}
+
+LSSnapshot::~LSSnapshot()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mDatabase);
+  MOZ_ASSERT(!mHasPendingStableStateCallback);
+  MOZ_ASSERT(!mHasPendingTimerCallback);
+  MOZ_ASSERT_IF(mInitialized, mSentFinish);
+
+  if (mActor) {
+    mActor->SendDeleteMeInternal();
+    MOZ_ASSERT(!mActor, "SendDeleteMeInternal should have cleared!");
+  }
+}
+
+void
+LSSnapshot::SetActor(LSSnapshotChild* aActor)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(aActor);
+  MOZ_ASSERT(!mActor);
+
+  mActor = aActor;
+}
+
+nsresult
+LSSnapshot::Init(const LSSnapshotInitInfo& aInitInfo,
+                 bool aExplicit)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(!mSelfRef);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mLoadState == LoadState::Initial);
+  MOZ_ASSERT(!mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  mSelfRef = this;
+
+  LoadState loadState = aInitInfo.loadState();
+
+  const nsTArray<LSItemInfo>& itemInfos = aInitInfo.itemInfos();
+  for (uint32_t i = 0; i < itemInfos.Length(); i++) {
+    const LSItemInfo& itemInfo = itemInfos[i];
+
+    const nsString& value = itemInfo.value();
+
+    if (loadState != LoadState::AllOrderedItems && !value.IsVoid()) {
+      mLoadedItems.PutEntry(itemInfo.key());
+    }
+
+    mValues.Put(itemInfo.key(), value);
+  }
+
+  if (loadState == LoadState::Partial) {
+    mInitLength = aInitInfo.totalLength();
+    mLength = mInitLength;
+  } else if (loadState == LoadState::AllOrderedKeys) {
+    mInitLength = aInitInfo.totalLength();
+  } else {
+    MOZ_ASSERT(loadState == LoadState::AllOrderedItems);
+  }
+
+  mExactUsage = aInitInfo.initialUsage();
+  mPeakUsage = aInitInfo.peakUsage();
+
+  mLoadState = aInitInfo.loadState();
+
+  mExplicit = aExplicit;
+
+#ifdef DEBUG
+  mInitialized = true;
+#endif
+
+  if (!mExplicit) {
+    mTimer = NS_NewTimer();
+    MOZ_ASSERT(mTimer);
+
+    ScheduleStableStateCallback();
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::GetLength(uint32_t* aResult)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MaybeScheduleStableStateCallback();
+
+  if (mLoadState == LoadState::Partial) {
+    *aResult = mLength;
+  } else {
+    *aResult = mValues.Count();
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::GetKey(uint32_t aIndex,
+                   nsAString& aResult)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MaybeScheduleStableStateCallback();
+
+  nsresult rv = EnsureAllKeys();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  aResult.SetIsVoid(true);
+  for (auto iter = mValues.ConstIter(); !iter.Done(); iter.Next()) {
+    if (aIndex == 0) {
+      aResult = iter.Key();
+      return NS_OK;
+    }
+    aIndex--;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::GetItem(const nsAString& aKey,
+                    nsAString& aResult)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MaybeScheduleStableStateCallback();
+
+  nsString result;
+  nsresult rv = GetItemInternal(aKey, Optional<nsString>(), result);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  aResult = result;
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::GetKeys(nsTArray<nsString>& aKeys)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MaybeScheduleStableStateCallback();
+
+  nsresult rv = EnsureAllKeys();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  for (auto iter = mValues.ConstIter(); !iter.Done(); iter.Next()) {
+    aKeys.AppendElement(iter.Key());
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::SetItem(const nsAString& aKey,
+                    const nsAString& aValue,
+                    LSNotifyInfo& aNotifyInfo)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MaybeScheduleStableStateCallback();
+
+  nsString oldValue;
+  nsresult rv =
+    GetItemInternal(aKey, Optional<nsString>(nsString(aValue)), oldValue);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  bool changed;
+  if (oldValue == aValue && oldValue.IsVoid() == aValue.IsVoid()) {
+    changed = false;
+  } else {
+    changed = true;
+
+    int64_t delta = static_cast<int64_t>(aValue.Length()) -
+                    static_cast<int64_t>(oldValue.Length());
+
+    if (oldValue.IsVoid()) {
+      delta += static_cast<int64_t>(aKey.Length());
+    }
+
+    rv = UpdateUsage(delta);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      if (oldValue.IsVoid()) {
+        mValues.Remove(aKey);
+      } else {
+        mValues.Put(aKey, oldValue);
+      }
+      return rv;
+    }
+
+    if (oldValue.IsVoid() && mLoadState == LoadState::Partial) {
+      mLength++;
+    }
+
+    LSSetItemInfo setItemInfo;
+    setItemInfo.key() = aKey;
+    setItemInfo.oldValue() = oldValue;
+    setItemInfo.value() = aValue;
+
+    mWriteInfos.AppendElement(std::move(setItemInfo));
+  }
+
+  aNotifyInfo.changed() = changed;
+  aNotifyInfo.oldValue() = oldValue;
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::RemoveItem(const nsAString& aKey,
+                       LSNotifyInfo& aNotifyInfo)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MaybeScheduleStableStateCallback();
+
+  nsString oldValue;
+  nsresult rv =
+    GetItemInternal(aKey, Optional<nsString>(VoidString()), oldValue);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  bool changed;
+  if (oldValue.IsVoid()) {
+    changed = false;
+  } else {
+    changed = true;
+
+    int64_t delta = -(static_cast<int64_t>(aKey.Length()) +
+                      static_cast<int64_t>(oldValue.Length()));
+
+    DebugOnly<nsresult> rv = UpdateUsage(delta);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+    if (mLoadState == LoadState::Partial) {
+      mLength--;
+    }
+
+    LSRemoveItemInfo removeItemInfo;
+    removeItemInfo.key() = aKey;
+    removeItemInfo.oldValue() = oldValue;
+
+    mWriteInfos.AppendElement(std::move(removeItemInfo));
+  }
+
+  aNotifyInfo.changed() = changed;
+  aNotifyInfo.oldValue() = oldValue;
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::Clear(LSNotifyInfo& aNotifyInfo)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MaybeScheduleStableStateCallback();
+
+  uint32_t length;
+  if (mLoadState == LoadState::Partial) {
+    length = mLength;
+    MOZ_ASSERT(length);
+
+    MOZ_ALWAYS_TRUE(mActor->SendLoaded());
+
+    mLoadedItems.Clear();
+    mUnknownItems.Clear();
+    mLength = 0;
+    mLoadState = LoadState::AllOrderedItems;
+  } else {
+    length = mValues.Count();
+  }
+
+  bool changed;
+  if (!length) {
+    changed = false;
+  } else {
+    changed = true;
+
+    DebugOnly<nsresult> rv = UpdateUsage(-mExactUsage);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+    mValues.Clear();
+
+    LSClearInfo clearInfo;
+
+    mWriteInfos.AppendElement(std::move(clearInfo));
+  }
+
+  aNotifyInfo.changed() = changed;
+
+  return NS_OK;
+}
+
+void
+LSSnapshot::MarkDirty()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  if (mDirty) {
+    return;
+  }
+
+  mDirty = true;
+
+  if (!mExplicit && !mHasPendingStableStateCallback) {
+    CancelTimer();
+
+    MOZ_ALWAYS_SUCCEEDS(Checkpoint());
+
+    MOZ_ALWAYS_SUCCEEDS(Finish());
+  } else {
+    MOZ_ASSERT(!mHasPendingTimerCallback);
+  }
+}
+
+nsresult
+LSSnapshot::End()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mExplicit);
+  MOZ_ASSERT(!mHasPendingStableStateCallback);
+  MOZ_ASSERT(!mHasPendingTimerCallback);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  nsresult rv = Checkpoint();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  RefPtr<LSSnapshot> kungFuDeathGrip = this;
+
+  rv = Finish();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (NS_WARN_IF(!mActor->SendPing())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+void
+LSSnapshot::ScheduleStableStateCallback()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mTimer);
+  MOZ_ASSERT(!mExplicit);
+  MOZ_ASSERT(!mHasPendingStableStateCallback);
+
+  CancelTimer();
+
+  nsCOMPtr<nsIRunnable> runnable = this;
+  nsContentUtils::RunInStableState(runnable.forget());
+
+  mHasPendingStableStateCallback = true;
+}
+
+void
+LSSnapshot::MaybeScheduleStableStateCallback()
+{
+  AssertIsOnOwningThread();
+
+  if (!mExplicit && !mHasPendingStableStateCallback) {
+    ScheduleStableStateCallback();
+  } else {
+    MOZ_ASSERT(!mHasPendingTimerCallback);
+  }
+}
+
+nsresult
+LSSnapshot::GetItemInternal(const nsAString& aKey,
+                            const Optional<nsString>& aValue,
+                            nsAString& aResult)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  nsString result;
+
+  switch (mLoadState) {
+    case LoadState::Partial: {
+      if (mValues.Get(aKey, &result)) {
+        MOZ_ASSERT(!result.IsVoid());
+      } else if (mLoadedItems.GetEntry(aKey) || mUnknownItems.GetEntry(aKey)) {
+        result.SetIsVoid(true);
+      } else {
+        if (NS_WARN_IF(!mActor->SendLoadItem(nsString(aKey), &result))) {
+          return NS_ERROR_FAILURE;
+        }
+
+        if (result.IsVoid()) {
+          mUnknownItems.PutEntry(aKey);
+        } else {
+          mLoadedItems.PutEntry(aKey);
+          mValues.Put(aKey, result);
+
+          if (mLoadedItems.Count() == mInitLength) {
+            mLoadedItems.Clear();
+            mUnknownItems.Clear();
+            mLength = 0;
+            mLoadState = LoadState::AllUnorderedItems;
+          }
+        }
+      }
+
+      if (aValue.WasPassed()) {
+        const nsString& value = aValue.Value();
+        if (!value.IsVoid()) {
+          mValues.Put(aKey, value);
+        } else if (!result.IsVoid()) {
+          mValues.Remove(aKey);
+        }
+      }
+
+      break;
+    }
+
+    case LoadState::AllOrderedKeys: {
+      if (mValues.Get(aKey, &result)) {
+        if (result.IsVoid()) {
+          if (NS_WARN_IF(!mActor->SendLoadItem(nsString(aKey), &result))) {
+            return NS_ERROR_FAILURE;
+          }
+
+          MOZ_ASSERT(!result.IsVoid());
+
+          mLoadedItems.PutEntry(aKey);
+          mValues.Put(aKey, result);
+
+          if (mLoadedItems.Count() == mInitLength) {
+            mLoadedItems.Clear();
+            MOZ_ASSERT(mLength == 0);
+            mLoadState = LoadState::AllOrderedItems;
+          }
+        }
+      } else {
+        result.SetIsVoid(true);
+      }
+
+      if (aValue.WasPassed()) {
+        const nsString& value = aValue.Value();
+        if (!value.IsVoid()) {
+          mValues.Put(aKey, value);
+        } else if (!result.IsVoid()) {
+          mValues.Remove(aKey);
+        }
+      }
+
+      break;
+    }
+
+    case LoadState::AllUnorderedItems:
+    case LoadState::AllOrderedItems: {
+      if (aValue.WasPassed()) {
+        const nsString& value = aValue.Value();
+        if (!value.IsVoid()) {
+          auto entry = mValues.LookupForAdd(aKey);
+          if (entry) {
+            result = entry.Data();
+            entry.Data() = value;
+          } else {
+            result.SetIsVoid(true);
+            entry.OrInsert([value]() { return value; });
+          }
+        } else {
+          if (auto entry = mValues.Lookup(aKey)) {
+            result = entry.Data();
+            MOZ_ASSERT(!result.IsVoid());
+            entry.Remove();
+          } else {
+            result.SetIsVoid(true);
+          }
+        }
+      } else {
+        if (mValues.Get(aKey, &result)) {
+          MOZ_ASSERT(!result.IsVoid());
+        } else {
+          result.SetIsVoid(true);
+        }
+      }
+
+      break;
+    }
+
+    default:
+      MOZ_CRASH("Bad state!");
+  }
+
+  aResult = result;
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::EnsureAllKeys()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+  MOZ_ASSERT(mLoadState != LoadState::Initial);
+
+  if (mLoadState == LoadState::AllOrderedKeys ||
+      mLoadState == LoadState::AllOrderedItems) {
+    return NS_OK;
+  }
+
+  nsTArray<nsString> keys;
+  if (NS_WARN_IF(!mActor->SendLoadKeys(&keys))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsDataHashtable<nsStringHashKey, nsString> newValues;
+
+  for (auto key : keys) {
+    newValues.Put(key, VoidString());
+  }
+
+  for (uint32_t index = 0; index < mWriteInfos.Length(); index++) {
+    const LSWriteInfo& writeInfo = mWriteInfos[index];
+
+    switch (writeInfo.type()) {
+      case LSWriteInfo::TLSSetItemInfo: {
+        newValues.Put(writeInfo.get_LSSetItemInfo().key(), VoidString());
+        break;
+      }
+      case LSWriteInfo::TLSRemoveItemInfo: {
+        newValues.Remove(writeInfo.get_LSRemoveItemInfo().key());
+        break;
+      }
+      case LSWriteInfo::TLSClearInfo: {
+        newValues.Clear();
+        break;
+      }
+
+      default:
+        MOZ_CRASH("Should never get here!");
+    }
+  }
+
+  MOZ_ASSERT_IF(mLoadState == LoadState::AllUnorderedItems,
+                newValues.Count() == mValues.Count());
+
+  for (auto iter = newValues.Iter(); !iter.Done(); iter.Next()) {
+    nsString value;
+    if (mValues.Get(iter.Key(), &value)) {
+      iter.Data() = value;
+    }
+  }
+
+  mValues.SwapElements(newValues);
+
+  if (mLoadState == LoadState::Partial) {
+    mUnknownItems.Clear();
+    mLength = 0;
+    mLoadState = LoadState::AllOrderedKeys;
+  } else {
+    MOZ_ASSERT(mLoadState == LoadState::AllUnorderedItems);
+
+    MOZ_ASSERT(mUnknownItems.Count() == 0);
+    MOZ_ASSERT(mLength == 0);
+    mLoadState = LoadState::AllOrderedItems;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::UpdateUsage(int64_t aDelta)
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mDatabase);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mPeakUsage >= mExactUsage);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  int64_t newExactUsage = mExactUsage + aDelta;
+  if (newExactUsage > mPeakUsage) {
+    int64_t minSize = newExactUsage - mPeakUsage;
+    int64_t requestedSize = minSize + 4096;
+    int64_t size;
+    if (NS_WARN_IF(!mActor->SendIncreasePeakUsage(requestedSize,
+                                                  minSize,
+                                                  &size))) {
+      return NS_ERROR_FAILURE;
+    }
+
+    MOZ_ASSERT(size >= 0);
+
+    if (size == 0) {
+      return NS_ERROR_FILE_NO_DEVICE_SPACE;
+    }
+
+    mPeakUsage += size;
+  }
+
+  mExactUsage = newExactUsage;
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::Checkpoint()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  if (!mWriteInfos.IsEmpty()) {
+    MOZ_ALWAYS_TRUE(mActor->SendCheckpoint(mWriteInfos));
+
+    mWriteInfos.Clear();
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LSSnapshot::Finish()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mDatabase);
+  MOZ_ASSERT(mActor);
+  MOZ_ASSERT(mInitialized);
+  MOZ_ASSERT(!mSentFinish);
+
+  MOZ_ALWAYS_TRUE(mActor->SendFinish());
+
+  mDatabase->NoteFinishedSnapshot(this);
+
+#ifdef DEBUG
+  mSentFinish = true;
+#endif
+
+  // Clear the self reference added in Init method.
+  MOZ_ASSERT(mSelfRef);
+  mSelfRef = nullptr;
+
+  return NS_OK;
+}
+
+void
+LSSnapshot::CancelTimer()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(mTimer);
+
+  if (mHasPendingTimerCallback) {
+    MOZ_ALWAYS_SUCCEEDS(mTimer->Cancel());
+    mHasPendingTimerCallback = false;
+  }
+}
+
+// static
+void
+LSSnapshot::TimerCallback(nsITimer* aTimer, void* aClosure)
+{
+  MOZ_ASSERT(aTimer);
+
+  auto* self = static_cast<LSSnapshot*>(aClosure);
+  MOZ_ASSERT(self);
+  MOZ_ASSERT(self->mTimer);
+  MOZ_ASSERT(SameCOMIdentity(self->mTimer, aTimer));
+  MOZ_ASSERT(!self->mHasPendingStableStateCallback);
+  MOZ_ASSERT(self->mHasPendingTimerCallback);
+
+  self->mHasPendingTimerCallback = false;
+
+  MOZ_ALWAYS_SUCCEEDS(self->Finish());
+}
+
+NS_IMPL_ISUPPORTS(LSSnapshot, nsIRunnable)
+
+NS_IMETHODIMP
+LSSnapshot::Run()
+{
+  AssertIsOnOwningThread();
+  MOZ_ASSERT(!mExplicit);
+  MOZ_ASSERT(mHasPendingStableStateCallback);
+  MOZ_ASSERT(!mHasPendingTimerCallback);
+
+  mHasPendingStableStateCallback = false;
+
+  MOZ_ALWAYS_SUCCEEDS(Checkpoint());
+
+  if (mDirty || !Preferences::GetBool("dom.storage.snapshot_reusing")) {
+    MOZ_ALWAYS_SUCCEEDS(Finish());
+  } else if (!mExplicit) {
+    MOZ_ASSERT(mTimer);
+
+    MOZ_ALWAYS_SUCCEEDS(
+      mTimer->InitWithNamedFuncCallback(TimerCallback,
+                                        this,
+                                        kSnapshotTimeoutMs,
+                                        nsITimer::TYPE_ONE_SHOT,
+                                        "LSSnapshot::TimerCallback"));
+
+    mHasPendingTimerCallback = true;
+  }
+
+  return NS_OK;
+}
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/LSSnapshot.h

@@ -0,0 +1,204 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_LSSnapshot_h
+#define mozilla_dom_localstorage_LSSnapshot_h
+
+namespace mozilla {
+namespace dom {
+
+class LSDatabase;
+class LSNotifyInfo;
+class LSSnapshotChild;
+class LSSnapshotInitInfo;
+class LSWriteInfo;
+
+class LSSnapshot final
+  : public nsIRunnable
+{
+public:
+  /**
+   * The LoadState expresses what subset of information a snapshot has from the
+   * authoritative Datastore in the parent process.  The initial snapshot is
+   * populated heuristically based on the size of the keys and size of the items
+   * (inclusive of the key value; item is key+value, not just value) of the
+   * entire datastore relative to the configured prefill limit (via pref
+   * "dom.storage.snapshot_prefill" exposed as gSnapshotPrefill in bytes).
+   *
+   * If there's less data than the limit, we send both keys and values and end
+   * up as AllOrderedItems.  If there's enough room for all the keys but not
+   * all the values, we end up as AllOrderedKeys with as many values present as
+   * would fit.  If there's not enough room for all the keys, then we end up as
+   * Partial with as many key-value pairs as will fit.
+   *
+   * The state AllUnorderedItems can only be reached by code getting items one
+   * by one.
+   */
+  enum class LoadState
+  {
+    /**
+     * Class constructed, Init(LSSnapshotInitInfo) has not been invoked yet.
+     */
+    Initial,
+    /**
+     * Some keys and their values are known.
+     */
+    Partial,
+    /**
+     * All the keys are known in order, but some values are unknown.
+     */
+    AllOrderedKeys,
+    /**
+     * All keys and their values are known, but in an arbitrary order.
+     */
+    AllUnorderedItems,
+    /**
+     * All keys and their values are known and are present in their canonical
+     * order.  This is everything, and is the preferred case.  The initial
+     * population will send this info when the size of all items is less than
+     * the prefill threshold.
+     *
+     * mValues will contain all keys and values, mLoadedItems and mUnknownItems
+     * are unused.
+     */
+    AllOrderedItems,
+    EndGuard
+  };
+
+private:
+  RefPtr<LSSnapshot> mSelfRef;
+
+  RefPtr<LSDatabase> mDatabase;
+
+  nsCOMPtr<nsITimer> mTimer;
+
+  LSSnapshotChild* mActor;
+
+  nsTHashtable<nsStringHashKey> mLoadedItems;
+  nsTHashtable<nsStringHashKey> mUnknownItems;
+  nsDataHashtable<nsStringHashKey, nsString> mValues;
+  nsTArray<LSWriteInfo> mWriteInfos;
+
+  uint32_t mInitLength;
+  uint32_t mLength;
+  int64_t mExactUsage;
+  int64_t mPeakUsage;
+
+  LoadState mLoadState;
+
+  bool mExplicit;
+  bool mHasPendingStableStateCallback;
+  bool mHasPendingTimerCallback;
+  bool mDirty;
+
+#ifdef DEBUG
+  bool mInitialized;
+  bool mSentFinish;
+#endif
+
+public:
+  explicit LSSnapshot(LSDatabase* aDatabase);
+
+  void
+  AssertIsOnOwningThread() const
+  {
+    NS_ASSERT_OWNINGTHREAD(LSSnapshot);
+  }
+
+  void
+  SetActor(LSSnapshotChild* aActor);
+
+  void
+  ClearActor()
+  {
+    AssertIsOnOwningThread();
+    MOZ_ASSERT(mActor);
+
+    mActor = nullptr;
+  }
+
+  bool
+  Explicit() const
+  {
+    return mExplicit;
+  }
+
+  nsresult
+  Init(const LSSnapshotInitInfo& aInitInfo,
+       bool aExplicit);
+
+  nsresult
+  GetLength(uint32_t* aResult);
+
+  nsresult
+  GetKey(uint32_t aIndex,
+         nsAString& aResult);
+
+  nsresult
+  GetItem(const nsAString& aKey,
+          nsAString& aResult);
+
+  nsresult
+  GetKeys(nsTArray<nsString>& aKeys);
+
+  nsresult
+  SetItem(const nsAString& aKey,
+          const nsAString& aValue,
+          LSNotifyInfo& aNotifyInfo);
+
+  nsresult
+  RemoveItem(const nsAString& aKey,
+             LSNotifyInfo& aNotifyInfo);
+
+  nsresult
+  Clear(LSNotifyInfo& aNotifyInfo);
+
+  void
+  MarkDirty();
+
+  nsresult
+  End();
+
+private:
+  ~LSSnapshot();
+
+  void
+  ScheduleStableStateCallback();
+
+  void
+  MaybeScheduleStableStateCallback();
+
+  nsresult
+  GetItemInternal(const nsAString& aKey,
+                  const Optional<nsString>& aValue,
+                  nsAString& aResult);
+
+  nsresult
+  EnsureAllKeys();
+
+  nsresult
+  UpdateUsage(int64_t aDelta);
+
+  nsresult
+  Checkpoint();
+
+  nsresult
+  Finish();
+
+  void
+  CancelTimer();
+
+  static void
+  TimerCallback(nsITimer* aTimer, void* aClosure);
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIRUNNABLE
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_LSSnapshot_h

dom/localstorage/LocalStorageCommon.cpp

@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LocalStorageCommon.h"
+
+namespace mozilla {
+namespace dom {
+
+namespace {
+
+Atomic<int32_t> gNextGenLocalStorageEnabled(-1);
+
+} // namespace
+
+const char16_t* kLocalStorageType = u"localStorage";
+
+bool
+NextGenLocalStorageEnabled()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (gNextGenLocalStorageEnabled == -1) {
+    bool enabled = Preferences::GetBool("dom.storage.next_gen", false);
+    gNextGenLocalStorageEnabled = enabled ? 1 : 0;
+  }
+
+  return !!gNextGenLocalStorageEnabled;
+}
+
+bool
+CachedNextGenLocalStorageEnabled()
+{
+  MOZ_ASSERT(gNextGenLocalStorageEnabled != -1);
+
+  return !!gNextGenLocalStorageEnabled;
+}
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/LocalStorageCommon.h

@@ -0,0 +1,247 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_LocalStorageCommon_h
+#define mozilla_dom_localstorage_LocalStorageCommon_h
+
+/*
+ * Local storage
+ * ~~~~~~~~~~~~~
+ *
+ * Implementation overview
+ * ~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The implementation is based on a per principal/origin cache (datastore)
+ * living in the main process and synchronous calls initiated from content
+ * processes.
+ * The IPC communication is managed by database actors which link to the
+ * datastore.
+ * The synchronous blocking of the main thread is done by using a special
+ * technique or by using standard synchronous IPC calls.
+ *
+ * General architecture
+ * ~~~~~~~~~~~~~~~~~~~~
+ * The current browser architecture consists of one main process and multiple
+ * content processes (there are other processes but for simplicity's sake, they
+ * are not mentioned here). The processes use the IPC communication to talk to
+ * each other. Local storage implementation uses the client-server model, so
+ * the main process manages all the data and content processes then request
+ * particular data from the main process. The main process is also called the
+ * parent or the parent side, the content process is then called the child or
+ * the child side.
+ *
+ * Datastores
+ * ~~~~~~~~~~
+ *
+ * A datastore provides a convenient way to access data for given origin. The
+ * data is always preloaded into memory and indexed using a hash table. This
+ * enables very fast access to particular stored items. There can be only one
+ * datastore per origin and exists solely on the parent side. It is represented
+ * by the "Datastore" class. A datastore instance is a ref counted object and
+ * lives on the PBackground thread, it is kept alive by database objects. When
+ * the last database object for given origin is destroyed, the associated
+ * datastore object is destroyed too.
+ *
+ * Databases
+ * ~~~~~~~~~
+ *
+ * A database allows direct access to a datastore from a content process. There
+ * can be multiple databases for the same origin, but they all share the same
+ * datastore.
+ * Databases use the PBackgroundLSDatabase IPDL protocol for IPC communication.
+ * Given the nature of local storage, most of PBackgroundLSDatabase messages
+ * are synchronous.
+ *
+ * On the parent side, the database is represented by the "Database" class that
+ * is a parent actor as well (implements the "PBackgroundLSDatabaseParent"
+ * interface). A database instance is a ref counted object and lives on the
+ * PBackground thread.
+ * All live database actors are tracked in an array.
+ *
+ * On the child side, the database is represented by the "LSDatabase" class
+ * that provides indirect access to a child actor. An LSDatabase instance is a
+ * ref counted object and lives on the main thread.
+ * The actual child actor is represented by the "LSDatabaseChild" class that
+ * implements the "PBackgroundLSDatabaseChild" interface. An "LSDatabaseChild"
+ * instance is not ref counted and lives on the main thread too.
+ *
+ * Synchronous blocking
+ * ~~~~~~~~~~~~~~~~~~~~
+ *
+ * Local storage is synchronous in nature which means the execution can't move
+ * forward until there's a reply for given method call.
+ * Since we have to use IPC anyway, we could just always use synchronous IPC
+ * messages for all local storage method calls. Well, there's a problem with
+ * that approach.
+ * If the main process needs to do some off PBackground thread stuff like
+ * getting info from principals on the main thread or some asynchronous stuff
+ * like directory locking before sending a reply to a synchronous message, then
+ * we would have to block the thread or spin the event loop which is usually a
+ * bad idea, especially in the main process.
+ * Instead, we can use a special thread in the content process called DOM File
+ * thread for communication with the main process using asynchronous messages
+ * and synchronously block the main thread until the DOM File thread is done
+ * (the main thread blocking is a bit more complicated, see the comment in
+ * RequestHelper::StartAndReturnResponse for more details).
+ * Anyway, the extra hop to the DOM File thread brings another overhead and
+ * latency. The final solution is to use a combination of the special thread
+ * for complex stuff like datastore preparation and synchronous IPC messages
+ * sent directly from the main thread for database access when data is already
+ * loaded from disk into memory.
+ *
+ * Requests
+ * ~~~~~~~~
+ *
+ * Requests are used to handle asynchronous high level datastore operations
+ * which are initiated in a content process and then processed in the parent
+ * process (for example, preparation of a datastore).
+ * Requests use the "PBackgroundLSRequest" IPDL protocol for IPC communication.
+ *
+ * On the parent side, the request is represented by the "LSRequestBase" class
+ * that is a parent actor as well (implements the "PBackgroundLSRequestParent"
+ * interface). It's an abstract class (contains pure virtual functions) so it
+ * can't be used to create instances.
+ * It also inherits from the "DatastoreOperationBase" class which is a generic
+ * base class for all datastore operations. The "DatastoreOperationsBase" class
+ * inherits from the "Runnable" class, so derived class instances are ref
+ * counted, can be dispatched to multiple threads and thus they are used on
+ * multiple threads. However, derived class instances can be created on the
+ * PBackground thread only.
+ *
+ * On the child side, the request is represented by the "RequestHelper" class
+ * that covers all the complexity needed to start a new request, handle
+ * responses and do safe main thread blocking at the same time.
+ * It inherits from the "Runnable" class, so instances are ref counted and
+ * they are internally used on multiple threads (specifically on the main
+ * thread and on the DOM File thread). Anyway, users should create and use
+ * instances of this class only on the main thread (apart from a special case
+ * when we need to cancel the request from an internal chromium IPC thread to
+ * prevent a dead lock involving CPOWs).
+ * The actual child actor is represented by the "LSRequestChild" class that
+ * implements the "PBackgroundLSRequestChild" interface. An "LSRequestChild"
+ * instance is not ref counted and lives on the DOM File thread.
+ * Request responses are passed using the "LSRequestChildCallback" interface.
+ *
+ * Preparation of a datastore
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The datastore preparation is needed to make sure a datastore is fully loaded
+ * into memory. Every datastore preparation produces a unique id (even if the
+ * datastore for given origin already exists).
+ * On the parent side, the preparation is handled by the "PrepareDatastoreOp"
+ * class which inherits from the "LSRequestBase" class. The preparation process
+ * on the parent side is quite complicated, it happens sequentially on multiple
+ * threads and is managed by a state machine.
+ * On the child side, the preparation is done in the LSObject::EnsureDatabase
+ * method using the "RequestHelper" class. The method starts a new preparation
+ * request and obtains a unique id produced by the parent (or an error code if
+ * the requested failed to complete).
+ *
+ * Linking databases to a datastore
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * A datastore exists only on the parent side, but it can be accessed from the
+ * content via database actors. Database actors are initiated on the child side
+ * and they need to be linked to a datastore on the parent side via an id. The
+ * datastore preparation process gives us the required id.
+ * The linking is initiated on the child side in the LSObject::EnsureDatabase
+ * method by calling SendPBackgroundLSDatabaseConstructor and finished in
+ * RecvPBackgroundLSDatabaseConstructor on the parent side.
+ *
+ * Actor migration
+ * ~~~~~~~~~~~~~~~
+ *
+ * In theory, the datastore preparation request could return a database actor
+ * directly (instead of returning an id intended for database linking to a
+ * datastore). However, as it was explained above, the preparation must be done
+ * on the DOM File thread and database objects are used on the main thread. The
+ * returned actor would have to be migrated from the DOM File thread to the
+ * main thread and that's something which our IPDL doesn't support yet.
+ *
+ * Exposing local storage
+ * ~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The implementation is exposed to the DOM via window.localStorage attribute.
+ * Local storage's sibling, session storage shares the same WebIDL interface
+ * for exposing it to web content, therefore there's an abstract class called
+ * "Storage" that handles some of the common DOM bindings stuff. Local storage
+ * specific functionality is defined in the "LSObject" derived class.
+ * The "LSObject" class is also a starting point for the datastore preparation
+ * and database linking.
+ *
+ * Local storage manager
+ * ~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The local storage manager exposes some of the features that need to be
+ * available only in the chrome code or tests. The manager is represented by
+ * the "LocalStorageManager2" class that implements the "nsIDOMStorageManager"
+ * interface.
+ */
+
+namespace mozilla {
+namespace dom {
+
+extern const char16_t* kLocalStorageType;
+
+/**
+ * Convenience data-structure to make it easier to track whether a value has
+ * changed and what its previous value was for notification purposes.  Instances
+ * are created on the stack by LSObject and passed to LSDatabase which in turn
+ * passes them onto LSSnapshot for final updating/population.  LSObject then
+ * generates an event, if appropriate.
+ */
+class MOZ_STACK_CLASS LSNotifyInfo
+{
+  bool mChanged;
+  nsString mOldValue;
+
+public:
+  LSNotifyInfo()
+    : mChanged(false)
+  { }
+
+  bool
+  changed() const
+  {
+    return mChanged;
+  }
+
+  bool&
+  changed()
+  {
+    return mChanged;
+  }
+
+  const nsString&
+  oldValue() const
+  {
+    return mOldValue;
+  }
+
+  nsString&
+  oldValue()
+  {
+    return mOldValue;
+  }
+};
+
+/**
+ * Main-thread-only check of LSNG being enabled, the value is latched once
+ * initialized so changing the preference during runtime has no effect.
+ */
+bool
+NextGenLocalStorageEnabled();
+
+/**
+ * Cached any-thread version of NextGenLocalStorageEnabled().
+ */
+bool
+CachedNextGenLocalStorageEnabled();
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_LocalStorageCommon_h

dom/localstorage/LocalStorageManager2.cpp

@@ -0,0 +1,430 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LocalStorageManager2.h"
+
+#include "LSObject.h"
+#include "mozilla/dom/Promise.h"
+
+namespace mozilla {
+namespace dom {
+
+namespace {
+
+class RequestResolver final
+  : public LSRequestChildCallback
+{
+  RefPtr<Promise> mPromise;
+
+public:
+  explicit RequestResolver(Promise* aPromise)
+    : mPromise(aPromise)
+  { }
+
+  NS_INLINE_DECL_REFCOUNTING(mozilla::dom::RequestResolver, override);
+
+private:
+  ~RequestResolver() = default;
+
+  void
+  HandleResponse(nsresult aResponse);
+
+  void
+  HandleResponse(const NullableDatastoreId& aDatastoreId);
+
+  // LSRequestChildCallback
+  void
+  OnResponse(const LSRequestResponse& aResponse) override;
+};
+
+class SimpleRequestResolver final
+  : public LSSimpleRequestChildCallback
+{
+  RefPtr<Promise> mPromise;
+
+public:
+  explicit SimpleRequestResolver(Promise* aPromise)
+    : mPromise(aPromise)
+  { }
+
+  NS_INLINE_DECL_REFCOUNTING(SimpleRequestResolver, override);
+
+private:
+  ~SimpleRequestResolver() = default;
+
+  void
+  HandleResponse(nsresult aResponse);
+
+  void
+  HandleResponse(bool aResponse);
+
+  // LSRequestChildCallback
+  void
+  OnResponse(const LSSimpleRequestResponse& aResponse) override;
+};
+
+nsresult
+CreatePromise(JSContext* aContext, Promise** aPromise)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aContext);
+
+  nsIGlobalObject* global =
+    xpc::NativeGlobal(JS::CurrentGlobalOrNull(aContext));
+  if (NS_WARN_IF(!global)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  ErrorResult result;
+  RefPtr<Promise> promise = Promise::Create(global, result);
+  if (result.Failed()) {
+    return result.StealNSResult();
+  }
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+nsresult
+CheckedPrincipalToPrincipalInfo(nsIPrincipal* aPrincipal,
+                                PrincipalInfo& aPrincipalInfo)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+
+  nsresult rv = PrincipalToPrincipalInfo(aPrincipal, &aPrincipalInfo);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (aPrincipalInfo.type() != PrincipalInfo::TContentPrincipalInfo &&
+      aPrincipalInfo.type() != PrincipalInfo::TSystemPrincipalInfo) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  return NS_OK;
+}
+
+} // namespace
+
+LocalStorageManager2::LocalStorageManager2()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(NextGenLocalStorageEnabled());
+}
+
+LocalStorageManager2::~LocalStorageManager2()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+NS_IMPL_ISUPPORTS(LocalStorageManager2,
+                  nsIDOMStorageManager,
+                  nsILocalStorageManager)
+
+NS_IMETHODIMP
+LocalStorageManager2::PrecacheStorage(nsIPrincipal* aPrincipal,
+                                      Storage** _retval)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(_retval);
+
+  // This method was created as part of the e10s-ification of the old LS
+  // implementation to perform a preload in the content/current process.  That's
+  // not how things work in LSNG.  Instead everything happens in the parent
+  // process, triggered by the official preloading spot,
+  // ContentParent::AboutToLoadHttpFtpWyciwygDocumentForChild.
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+LocalStorageManager2::CreateStorage(mozIDOMWindow* aWindow,
+                                    nsIPrincipal* aPrincipal,
+                                    const nsAString& aDocumentURI,
+                                    bool aPrivate,
+                                    Storage** _retval)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(_retval);
+
+  nsCOMPtr<nsPIDOMWindowInner> inner = nsPIDOMWindowInner::From(aWindow);
+
+  RefPtr<LSObject> object;
+  nsresult rv = LSObject::CreateForPrincipal(inner,
+                                             aPrincipal,
+                                             aDocumentURI,
+                                             aPrivate,
+                                             getter_AddRefs(object));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  object.forget(_retval);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+LocalStorageManager2::GetStorage(mozIDOMWindow* aWindow,
+                                 nsIPrincipal* aPrincipal,
+                                 bool aPrivate,
+                                 Storage** _retval)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(_retval);
+
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+LocalStorageManager2::CloneStorage(Storage* aStorageToCloneFrom)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aStorageToCloneFrom);
+
+  // Cloning is specific to sessionStorage; state is forked when a new tab is
+  // opened from an existing tab.
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+LocalStorageManager2::CheckStorage(nsIPrincipal* aPrincipal,
+                                   Storage *aStorage,
+                                   bool* _retval)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(aStorage);
+  MOZ_ASSERT(_retval);
+
+  // Only used by sessionStorage.
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+LocalStorageManager2::GetNextGenLocalStorageEnabled(bool* aResult)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aResult);
+
+  *aResult = NextGenLocalStorageEnabled();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+LocalStorageManager2::Preload(nsIPrincipal* aPrincipal,
+                              JSContext* aContext,
+                              nsISupports** _retval)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(_retval);
+
+  nsresult rv;
+
+  RefPtr<Promise> promise;
+
+  if (aContext) {
+    rv = CreatePromise(aContext, getter_AddRefs(promise));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  }
+
+  LSRequestPrepareDatastoreParams params;
+  params.createIfNotExists() = false;
+
+  rv = CheckedPrincipalToPrincipalInfo(aPrincipal,
+                                       params.principalInfo());
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = StartRequest(promise, params);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  promise.forget(_retval);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+LocalStorageManager2::IsPreloaded(nsIPrincipal* aPrincipal,
+                                  JSContext* aContext,
+                                  nsISupports** _retval)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPrincipal);
+  MOZ_ASSERT(_retval);
+
+  RefPtr<Promise> promise;
+  nsresult rv = CreatePromise(aContext, getter_AddRefs(promise));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  LSSimpleRequestPreloadedParams params;
+
+  rv = CheckedPrincipalToPrincipalInfo(aPrincipal,
+                                       params.principalInfo());
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = StartSimpleRequest(promise, params);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  promise.forget(_retval);
+  return NS_OK;
+}
+
+nsresult
+LocalStorageManager2::StartRequest(Promise* aPromise,
+                                   const LSRequestParams& aParams)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  PBackgroundChild* backgroundActor =
+    BackgroundChild::GetOrCreateForCurrentThread();
+  if (NS_WARN_IF(!backgroundActor)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<RequestResolver> resolver = new RequestResolver(aPromise);
+
+  auto actor = new LSRequestChild(resolver);
+
+  if (!backgroundActor->SendPBackgroundLSRequestConstructor(actor, aParams)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+LocalStorageManager2::StartSimpleRequest(Promise* aPromise,
+                                         const LSSimpleRequestParams& aParams)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPromise);
+
+  PBackgroundChild* backgroundActor =
+    BackgroundChild::GetOrCreateForCurrentThread();
+  if (NS_WARN_IF(!backgroundActor)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<SimpleRequestResolver> resolver = new SimpleRequestResolver(aPromise);
+
+  auto actor = new LSSimpleRequestChild(resolver);
+
+  if (!backgroundActor->SendPBackgroundLSSimpleRequestConstructor(actor,
+                                                                  aParams)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+void
+RequestResolver::HandleResponse(nsresult aResponse)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (!mPromise) {
+    return;
+  }
+
+  mPromise->MaybeReject(aResponse);
+}
+
+void
+RequestResolver::HandleResponse(const NullableDatastoreId& aDatastoreId)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (!mPromise) {
+    return;
+  }
+
+  switch (aDatastoreId.type()) {
+    case NullableDatastoreId::Tnull_t:
+      mPromise->MaybeResolve(JS::NullHandleValue);
+      break;
+
+    case NullableDatastoreId::Tuint64_t:
+      mPromise->MaybeResolve(aDatastoreId.get_uint64_t());
+      break;
+
+   default:
+      MOZ_CRASH("Unknown datastore id type!");
+  }
+}
+
+void
+RequestResolver::OnResponse(const LSRequestResponse& aResponse)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  switch (aResponse.type()) {
+    case LSRequestResponse::Tnsresult:
+      HandleResponse(aResponse.get_nsresult());
+      break;
+
+    case LSRequestResponse::TLSRequestPrepareDatastoreResponse:
+      HandleResponse(
+        aResponse.get_LSRequestPrepareDatastoreResponse().datastoreId());
+      break;
+   default:
+      MOZ_CRASH("Unknown response type!");
+  }
+}
+
+void
+SimpleRequestResolver::HandleResponse(nsresult aResponse)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mPromise);
+
+  mPromise->MaybeReject(aResponse);
+}
+
+void
+SimpleRequestResolver::HandleResponse(bool aResponse)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mPromise);
+
+  mPromise->MaybeResolve(aResponse);
+}
+
+void
+SimpleRequestResolver::OnResponse(const LSSimpleRequestResponse& aResponse)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  switch (aResponse.type()) {
+    case LSSimpleRequestResponse::Tnsresult:
+      HandleResponse(aResponse.get_nsresult());
+      break;
+
+    case LSSimpleRequestResponse::TLSSimpleRequestPreloadedResponse:
+      HandleResponse(
+        aResponse.get_LSSimpleRequestPreloadedResponse().preloaded());
+      break;
+
+   default:
+      MOZ_CRASH("Unknown response type!");
+  }
+}
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/LocalStorageManager2.h

@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_LocalStorageManager2_h
+#define mozilla_dom_localstorage_LocalStorageManager2_h
+
+#include "nsIDOMStorageManager.h"
+#include "nsILocalStorageManager.h"
+
+namespace mozilla {
+namespace dom {
+
+class LSRequestParams;
+class LSSimpleRequestParams;
+class Promise;
+
+/**
+ * Under LSNG this exposes nsILocalStorageManager::Preload to ContentParent to
+ * trigger preloading.  Otherwise, this is basically just a place for test logic
+ * that doesn't make sense to put directly on the Storage WebIDL interface.
+ *
+ * Previously, the nsIDOMStorageManager XPCOM interface was also used by
+ * nsGlobalWindowInner to interact with LocalStorage, but in these de-XPCOM
+ * days, we've moved to just directly reference the relevant concrete classes
+ * (ex: LSObject) directly.
+ *
+ * Note that testing methods are now also directly exposed on the Storage WebIDL
+ * interface for simplicity/sanity.
+ */
+class LocalStorageManager2 final
+  : public nsIDOMStorageManager
+  , public nsILocalStorageManager
+{
+public:
+  LocalStorageManager2();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDOMSTORAGEMANAGER
+  NS_DECL_NSILOCALSTORAGEMANAGER
+
+private:
+  ~LocalStorageManager2();
+
+  /**
+   * Helper to trigger an LSRequest and resolve/reject the provided promise when
+   * the result comes in.  This routine is notable because the LSRequest
+   * mechanism is normally used synchronously from content, but here it's
+   * exposed asynchronously.
+   */
+  nsresult
+  StartRequest(Promise* aPromise,
+               const LSRequestParams& aParams);
+
+  /**
+   * Helper to trigger an LSSimpleRequst and resolve/reject the provided promise
+   * when the result comes in.
+   */
+  nsresult
+  StartSimpleRequest(Promise* aPromise,
+                     const LSSimpleRequestParams& aParams);
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_localstorage_LocalStorageManager2_h

dom/localstorage/PBackgroundLSDatabase.ipdl

@@ -0,0 +1,148 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PBackground;
+include protocol PBackgroundLSSnapshot;
+
+include "mozilla/dom/localstorage/SerializationHelpers.h";
+
+using mozilla::dom::LSSnapshot::LoadState
+  from "mozilla/dom/LSSnapshot.h";
+
+namespace mozilla {
+namespace dom {
+
+/**
+ * LocalStorage key/value pair wire representations.  `value` may be void in
+ * cases where there is a value but it is not being sent for memory/bandwidth
+ * conservation purposes.  (It's not possible to have a null/undefined `value`
+ * as Storage is defined explicitly as a String store.)
+ */
+struct LSItemInfo
+{
+  nsString key;
+  nsString value;
+};
+
+/**
+ * Initial LSSnapshot state as produced by Datastore::GetSnapshotInitInfo.  See
+ * `LSSnapshot::LoadState` for more details about the possible states and a
+ * high level overview.
+ */
+struct LSSnapshotInitInfo
+{
+  /**
+   * As many key/value or key/void pairs as the snapshot prefill byte budget
+   * allowed.
+   */
+  LSItemInfo[] itemInfos;
+  /**
+   * The total number of key/value pairs in LocalStorage for this origin at the
+   * time the snapshot was created.  (And the point of the snapshot is to
+   * conceptually freeze the state of the Datastore in time, so this value does
+   * not change despite what other LSDatabase objects get up to in other
+   * processes.)
+   */
+  uint32_t totalLength;
+  /**
+   * The current amount of LocalStorage usage as measured by the summing the
+   * nsString Length() of both the key and the value over all stored pairs.
+   */
+  int64_t initialUsage;
+  /**
+   * The amount of storage allowed to be used by the Snapshot without requesting
+   * more storage space via IncreasePeakUsage.  This is the `initialUsage` plus
+   * 0 or more bytes of space.  If space was available, the increase will be the
+   * `requestedSize` from the PBackgroundLSSnapshot constructor.  If the
+   * LocalStorage usage was already close to the limit, then the fallback is the
+   * `minSize` requested, or 0 if there wasn't space for that.
+   */
+  int64_t peakUsage;
+  // See `LSSnapshot::LoadState` in `LSSnapshot.h`
+  LoadState loadState;
+};
+
+/**
+ * This protocol is asynchronously created via constructor on PBackground but
+ * has synchronous semantics from the perspective of content on the main thread.
+ * The construction potentially involves waiting for disk I/O to load the
+ * LocalStorage data from disk as well as related QuotaManager checks, so async
+ * calls to PBackground are the only viable mechanism because blocking
+ * PBackground is not acceptable.  (Note that an attempt is made to minimize any
+ * I/O latency by triggering preloading from
+ * ContentParent::AboutToLoadHttpFtpWyciwygDocumentForChild, the central place
+ * for pre-loading.)
+ */
+sync protocol PBackgroundLSDatabase
+{
+  manager PBackground;
+  manages PBackgroundLSSnapshot;
+
+parent:
+  // The DeleteMe message is used to avoid a race condition between the parent
+  // actor and the child actor. The PBackgroundLSDatabase protocol could be
+  // simply destroyed by sending the __delete__ message from the child side.
+  // However, that would destroy the child actor immediatelly and the parent
+  // could be sending a message to the child at the same time resulting in a
+  // routing error since the child actor wouldn't exist anymore. A routing
+  // error typically causes a crash. The race can be prevented by doing the
+  // teardown in two steps. First, we send the DeleteMe message to the parent
+  // and the parent then sends the __delete__ message to the child.
+  async DeleteMe();
+
+  /**
+   * Sent in response to a `RequestAllowToClose` message once the snapshot
+   * cleanup has happened OR from LSDatabase's destructor if AllowToClose has
+   * not already been reported.
+   */
+  async AllowToClose();
+
+  /**
+   * Invoked to create an LSSnapshot backed by a Snapshot in PBackground that
+   * presents an atomic and consistent view of the state of the authoritative
+   * Datastore state in the parent.
+   *
+   * This needs to be synchronous because LocalStorage's semantics are
+   * synchronous.  Note that the Datastore in the PBackground parent already
+   * has the answers to this request immediately available without needing to
+   * consult any other threads or perform any I/O.  Additionally, the response
+   * is explicitly bounded in size by the tunable snapshot prefill byte limit.
+   *
+   * @param increasePeakUsage
+   *   Whether the parent should attempt to pre-allocate some amount of quota
+   *   usage to the Snapshot.
+   */
+  sync PBackgroundLSSnapshot(nsString documentURI,
+                             bool increasePeakUsage,
+                             int64_t requestedSize,
+                             int64_t minSize)
+    returns (LSSnapshotInitInfo initInfo);
+
+child:
+  /**
+   * Only sent by the parent in response to the child's DeleteMe request.
+   */
+  async __delete__();
+
+  /**
+   * Request to close the LSDatabase, checkpointing and finishing any
+   * outstanding snapshots so no state is lost.  This request is issued when
+   * QuotaManager is shutting down or is aborting operations for an origin or
+   * process.  Once the snapshot has cleaned up, AllowToClose will be sent to
+   * the parent.
+   *
+   * Note that the QuotaManager shutdown process is more likely to happen in
+   * unit tests where we explicitly reset the QuotaManager.  At runtime, we
+   * expect windows to be closed and content processes terminated well before
+   * QuotaManager shutdown would actually occur.
+   *
+   * Also, Operations are usually aborted for an origin due to privacy API's
+   * clearing data for an origin.  Operations are aborted for a process by
+   * ContentParent::ShutDownProcess.
+   */
+  async RequestAllowToClose();
+};
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/PBackgroundLSObserver.ipdl

@@ -0,0 +1,57 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PBackground;
+
+include PBackgroundSharedTypes;
+
+namespace mozilla {
+namespace dom {
+
+/**
+ * The observer protocol sends "storage" event notifications for changes to
+ * LocalStorage that take place in other processes as their Snapshots are
+ * Checkpointed to the canonical Datastore in the parent process.  Same-process
+ * notifications are generated as mutations happen.
+ *
+ * Note that mutations are never generated for redundant mutations.  Setting the
+ * key "foo" to have value "bar" when it already has value "bar" will never
+ * result in a "storage" event.
+ */
+async protocol PBackgroundLSObserver
+{
+  manager PBackground;
+
+parent:
+  /**
+   * Sent by the LSObserver's destructor when it's going away.  Any Observe
+   * messages received after this is sent will be ignored.  Which is fine,
+   * because there should be nothing around left to hear.  In the event a new
+   * page came into existence, its Observer creation will happen (effectively)
+   * synchronously.
+   */
+  async DeleteMe();
+
+child:
+  /**
+   * Only sent by the parent in response to a deletion request.
+   */
+  async __delete__();
+
+  /**
+   * Sent by the parent process as Snapshots from other processes are
+   * Checkpointed, applying their mutations.  The child actor currently directly
+   * shunts these to Storage::NotifyChange to generate "storage" events for
+   * immediate dispatch.
+   */
+  async Observe(PrincipalInfo principalInfo,
+                uint32_t privateBrowsingId,
+                nsString documentURI,
+                nsString key,
+                nsString oldValue,
+                nsString newValue);
+};
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/PBackgroundLSRequest.ipdl

@@ -0,0 +1,103 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PBackground;
+
+using struct mozilla::null_t
+  from "ipc/IPCMessageUtils.h";
+
+namespace mozilla {
+namespace dom {
+
+union NullableDatastoreId
+{
+  null_t;
+  uint64_t;
+};
+
+struct LSRequestPrepareDatastoreResponse
+{
+  NullableDatastoreId datastoreId;
+};
+
+struct LSRequestPrepareObserverResponse
+{
+  uint64_t observerId;
+};
+
+/**
+ * Discriminated union which can contain an error code (`nsresult`) or
+ * particular request response.
+ */
+union LSRequestResponse
+{
+  nsresult;
+  LSRequestPrepareDatastoreResponse;
+  LSRequestPrepareObserverResponse;
+};
+
+/**
+ * An asynchronous protocol for issuing requests that are used in a synchronous
+ * fashion by LocalStorage via LSObject's RequestHelper mechanism.  This differs
+ * from LSSimpleRequest which is implemented and used asynchronously.
+ *
+ * See `PBackgroundLSSharedTypes.ipdlh` for more on the request types, the
+ * response types above for their corresponding responses, and `RequestHelper`
+ * for more on the usage and lifecycle of this mechanism.
+ */
+protocol PBackgroundLSRequest
+{
+  manager PBackground;
+
+parent:
+  // The Cancel message is used to avoid a possible dead lock caused by a CPOW
+  // sending a synchronous message from the main thread in the chrome process
+  // to the main thread in the content process at the time we are blocking
+  // the main thread in the content process to handle a request.
+  // We use the PBackground thread on the parent side to handle requests, but
+  // sometimes we need to get information from principals and that's currently
+  // only possible on the main thread. So if the main thread in the chrome
+  // process is blocked by a CPOW operation, our request must wait for the CPOW
+  // operation to complete. However the CPOW operation can't complete either
+  // because we are blocking the main thread in the content process.
+  // The dead lock is prevented by canceling our nested event loop in the
+  // content process when we receive a synchronous IPC message from the parent.
+  //
+  // Note that cancellation isn't instantaneous.  It's just an asynchronous flow
+  // that definitely doesn't involve the main thread in the parent process, so
+  // we're guaranteed to unblock the main-thread in the content process and
+  // allow the sync IPC to make progress.  When Cancel() is received by the
+  // parent, it will Send__delete__.  The child will either send Cancel or
+  // Finish, but not both.
+  async Cancel();
+
+  /**
+   * Sent by the child in response to Ready, requesting that __delete__ be sent
+   * with the result.  The child will either send Finish or Cancel, but not
+   * both.  No further message will be sent from the child after invoking one.
+   */
+  async Finish();
+
+child:
+  /**
+   * The deletion is sent with the result of the request directly in response to
+   * either Cancel or Finish.
+   */
+  async __delete__(LSRequestResponse response);
+
+  /**
+   * Sent by the parent when it has completed whatever async stuff it needs to
+   * do and is ready to send the results.  It then awaits the Finish() call to
+   * send the results.  This may seem redundant, but it's not.  If the
+   * __delete__ was sent directly, it's possible there could be a race where
+   * Cancel() would be received by the parent after it had already sent
+   * __delete__.  (Which may no longer be fatal thanks to improvements to the
+   * IPC layer, but it would still lead to warnings, etc.  And we don't
+   * expect PBackground to be highly contended nor the DOM File thread.)
+   */
+  async Ready();
+};
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/PBackgroundLSSharedTypes.ipdlh

@@ -0,0 +1,38 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include PBackgroundSharedTypes;
+
+namespace mozilla {
+namespace dom {
+
+struct LSRequestPrepareDatastoreParams
+{
+  PrincipalInfo principalInfo;
+  bool createIfNotExists;
+};
+
+struct LSRequestPrepareObserverParams
+{
+  PrincipalInfo principalInfo;
+};
+
+union LSRequestParams
+{
+  LSRequestPrepareDatastoreParams;
+  LSRequestPrepareObserverParams;
+};
+
+struct LSSimpleRequestPreloadedParams
+{
+  PrincipalInfo principalInfo;
+};
+
+union LSSimpleRequestParams
+{
+  LSSimpleRequestPreloadedParams;
+};
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/PBackgroundLSSimpleRequest.ipdl

@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PBackground;
+
+namespace mozilla {
+namespace dom {
+
+/**
+ * Response to a `LSSimpleRequestPreloadedParams` request indicating whether the
+ * origin was preloaded.
+ */
+struct LSSimpleRequestPreloadedResponse
+{
+  bool preloaded;
+};
+
+/**
+ * Discriminated union which can contain an error code (`nsresult`) or
+ * particular simple request response.
+ */
+union LSSimpleRequestResponse
+{
+  nsresult;
+  LSSimpleRequestPreloadedResponse;
+};
+
+/**
+ * Simple requests are async-only from both a protocol perspective and the
+ * manner in which they're used.  In comparison, PBackgroundLSRequests are
+ * async only from a protocol perspective; they are used synchronously from the
+ * main thread via LSObject's RequestHelper mechanism.  (With the caveat that
+ * nsILocalStorageManager does expose LSRequests asynchronously.)
+ *
+ * These requests use the common idiom where the arguments to the request are
+ * sent in the constructor and the result is sent in the __delete__ response.
+ * Request types are indicated by the Params variant used and those live in
+ * `PBackgroundLSSharedTypes.ipdlh`.
+ */
+protocol PBackgroundLSSimpleRequest
+{
+  manager PBackground;
+
+child:
+  async __delete__(LSSimpleRequestResponse response);
+};
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/PBackgroundLSSnapshot.ipdl

@@ -0,0 +1,114 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PBackground;
+include protocol PBackgroundLSDatabase;
+
+namespace mozilla {
+namespace dom {
+
+struct LSSetItemInfo
+{
+  nsString key;
+  nsString oldValue;
+  nsString value;
+};
+
+struct LSRemoveItemInfo
+{
+  nsString key;
+  nsString oldValue;
+};
+
+struct LSClearInfo
+{
+};
+
+/**
+ * Union of LocalStorage mutation types.
+ */
+union LSWriteInfo
+{
+  LSSetItemInfo;
+  LSRemoveItemInfo;
+  LSClearInfo;
+};
+
+sync protocol PBackgroundLSSnapshot
+{
+  manager PBackgroundLSDatabase;
+
+parent:
+  async DeleteMe();
+
+  async Checkpoint(LSWriteInfo[] writeInfos);
+
+  async Finish();
+
+  async Loaded();
+
+  /**
+   * Invoked on demand to load an item that didn't fit into the initial
+   * snapshot prefill.
+   *
+   * This needs to be synchronous because LocalStorage's semantics are
+   * synchronous.  Note that the Snapshot in the PBackground parent already
+   * has the answers to this request immediately available without needing to
+   * consult any other threads or perform any I/O.
+   */
+  sync LoadItem(nsString key)
+    returns (nsString value);
+
+  /**
+   * Invoked on demand to load all keys in in their canonical order if they
+   * didn't fit into the initial snapshot prefill.
+   *
+   * This needs to be synchronous because LocalStorage's semantics are
+   * synchronous.  Note that the Snapshot in the PBackground parent already
+   * has the answers to this request immediately available without needing to
+   * consult any other threads or perform any I/O.
+   */
+  sync LoadKeys()
+    returns (nsString[] keys);
+
+  /**
+   * This needs to be synchronous because LocalStorage's semantics are
+   * synchronous.  Note that the Snapshot in the PBackground parent typically
+   * doesn't need to consult any other threads or perform any I/O to handle
+   * this request.  However, it has to call a quota manager method that can
+   * potentially do I/O directly on the PBackground thread.  It can only happen
+   * rarely in a storage pressure (low storage space) situation.  Specifically,
+   * after we get a list of origin directories for eviction, we will delete
+   * them directly on the PBackground thread.  This doesn't cause any
+   * performance problems, but avoiding I/O completely might need to be done as
+   * a futher optimization.
+   */
+  sync IncreasePeakUsage(int64_t requestedSize, int64_t minSize)
+    returns (int64_t size);
+
+  // A synchronous ping to the parent actor to confirm that the parent actor
+  // has received previous async message. This should only be used by the
+  // snapshotting code to end an explicit snapshot.
+  sync Ping();
+
+child:
+  /**
+   * Compels the child LSSnapshot to Checkpoint() and Finish(), effectively
+   * compelling the snapshot to flush any issued mutations and close itself.
+   * The child LSSnapshot does that either immediately if it's just waiting
+   * to be reused or when it gets into a stable state.
+   *
+   * This message is expected to be sent in the following two cases only:
+   *   1. The state of the underlying Datastore starts to differ from the state
+   *      captured at the time of snapshot creation.
+   *   2. The last private browsing context exits.  And in that case we expect
+   *      all private browsing globals to already have been destroyed.
+   */
+  async MarkDirty();
+
+  async __delete__();
+};
+
+} // namespace dom
+} // namespace mozilla

dom/localstorage/ReportInternalError.cpp

@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ReportInternalError.h"
+
+#include "mozilla/IntegerPrintfMacros.h"
+
+#include "nsContentUtils.h"
+#include "nsPrintfCString.h"
+
+namespace mozilla {
+namespace dom {
+namespace localstorage {
+
+void
+ReportInternalError(const char* aFile, uint32_t aLine, const char* aStr)
+{
+  // Get leaf of file path
+  for (const char* p = aFile; *p; ++p) {
+    if (*p == '/' && *(p + 1)) {
+      aFile = p + 1;
+    }
+  }
+
+  nsContentUtils::LogSimpleConsoleError(
+    NS_ConvertUTF8toUTF16(nsPrintfCString(
+                          "LocalStorage %s: %s:%" PRIu32, aStr, aFile, aLine)),
+    "localstorage", false);
+}
+
+} // namespace localstorage
+} // namespace dom
+} // namespace mozilla

dom/localstorage/ReportInternalError.h

@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_ReportInternalError_h
+#define mozilla_dom_localstorage_ReportInternalError_h
+
+#include "nsDebug.h"
+
+#define LS_WARNING(...)                                                        \
+  do {                                                                         \
+    nsPrintfCString s(__VA_ARGS__);                                            \
+    mozilla::dom::localstorage::ReportInternalError(__FILE__,                  \
+                                                    __LINE__,                  \
+                                                    s.get());                  \
+    NS_WARNING(s.get());                                                       \
+  } while (0)
+
+namespace mozilla {
+namespace dom {
+namespace localstorage {
+
+void
+ReportInternalError(const char* aFile, uint32_t aLine, const char* aStr);
+
+} // namespace localstorage
+} // namespace dom
+} // namespace mozilla
+
+#endif  // mozilla_dom_localstorage_ReportInternalError_h

dom/localstorage/SerializationHelpers.h

@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_localstorage_SerializationHelpers_h
+#define mozilla_dom_localstorage_SerializationHelpers_h
+
+#include "ipc/IPCMessageUtils.h"
+
+#include "mozilla/dom/LSSnapshot.h"
+
+namespace IPC {
+
+template <>
+struct ParamTraits<mozilla::dom::LSSnapshot::LoadState> :
+  public ContiguousEnumSerializer<mozilla::dom::LSSnapshot::LoadState,
+                                  mozilla::dom::LSSnapshot::LoadState::Initial,
+                                  mozilla::dom::LSSnapshot::LoadState::EndGuard>
+{ };
+
+} // namespace IPC
+
+#endif // mozilla_dom_localstorage_SerializationHelpers_h

dom/localstorage/moz.build

@@ -0,0 +1,64 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+XPCSHELL_TESTS_MANIFESTS += [
+    'test/unit/xpcshell.ini'
+]
+
+TEST_HARNESS_FILES.xpcshell.dom.localstorage.test.unit += [
+    'test/unit/databaseShadowing-shared.js',
+]
+
+XPIDL_SOURCES += [
+    'nsILocalStorageManager.idl',
+]
+
+XPIDL_MODULE = 'dom_localstorage'
+
+EXPORTS.mozilla.dom.localstorage += [
+    'ActorsParent.h',
+    'SerializationHelpers.h',
+]
+
+EXPORTS.mozilla.dom += [
+    'LocalStorageCommon.h',
+    'LocalStorageManager2.h',
+    'LSObject.h',
+    'LSObserver.h',
+    'LSSnapshot.h',
+]
+
+UNIFIED_SOURCES += [
+    'ActorsChild.cpp',
+    'ActorsParent.cpp',
+    'LocalStorageCommon.cpp',
+    'LocalStorageManager2.cpp',
+    'LSDatabase.cpp',
+    'LSObject.cpp',
+    'LSObserver.cpp',
+    'LSSnapshot.cpp',
+    'ReportInternalError.cpp',
+]
+
+IPDL_SOURCES += [
+    'PBackgroundLSDatabase.ipdl',
+    'PBackgroundLSObserver.ipdl',
+    'PBackgroundLSRequest.ipdl',
+    'PBackgroundLSSharedTypes.ipdlh',
+    'PBackgroundLSSimpleRequest.ipdl',
+    'PBackgroundLSSnapshot.ipdl',
+]
+
+include('/ipc/chromium/chromium-config.mozbuild')
+
+FINAL_LIBRARY = 'xul'
+
+if CONFIG['GNU_CXX']:
+    CXXFLAGS += ['-Wno-error=shadow']
+
+LOCAL_INCLUDES += [
+    '/dom/file/ipc',
+]

dom/localstorage/nsILocalStorageManager.idl

@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIPrincipal;
+
+/**
+ * Methods specific to LocalStorage, see nsIDOMStorageManager for methods shared
+ * with SessionStorage.  Methods may migrate there as SessionStorage is
+ * overhauled.
+ */
+[scriptable, builtinclass, uuid(d4f534da-2744-4db3-8774-8b187c64ade9)]
+interface nsILocalStorageManager : nsISupports
+{
+  readonly attribute boolean nextGenLocalStorageEnabled;
+
+  /**
+   * Trigger preload of LocalStorage for the given principal.  For use by
+   * ContentParent::AboutToLoadHttpFtpWyciwygDocumentForChild to maximize the
+   * amount of time we have to load the data off disk before the page might
+   * attempt to touch LocalStorage.
+   *
+   * This method will not create a QuotaManager-managed directory on disk if
+   * one does not already exist for the principal.
+   */
+  [implicit_jscontext] nsISupports
+  preload(in nsIPrincipal aPrincipal);
+
+  [implicit_jscontext] nsISupports
+  isPreloaded(in nsIPrincipal aPrincipal);
+};

dom/localstorage/test/unit/databaseShadowing-shared.js

@@ -0,0 +1,114 @@
+const principalInfos = [
+  { url: "http://example.com", attrs: {} },
+
+  { url: "http://origin.test", attrs: {} },
+
+  { url: "http://prefix.test", attrs: {} },
+  { url: "http://prefix.test", attrs: { userContextId: 10 } },
+
+  { url: "http://pattern.test", attrs: { userContextId: 15 } },
+  { url: "http://pattern.test:8080", attrs: { userContextId: 15 } },
+  { url: "https://pattern.test", attrs: { userContextId: 15 } },
+];
+
+function enableNextGenLocalStorage()
+{
+  info("Setting pref");
+
+  Services.prefs.setBoolPref("dom.storage.next_gen", true);
+}
+
+function disableNextGenLocalStorage()
+{
+  info("Setting pref");
+
+  Services.prefs.setBoolPref("dom.storage.next_gen", false);
+}
+
+function storeData()
+{
+  for (let i = 0; i < principalInfos.length; i++) {
+    let principalInfo = principalInfos[i];
+    let principal = getPrincipal(principalInfo.url, principalInfo.attrs);
+
+    info("Getting storage");
+
+    let storage = getLocalStorage(principal);
+
+    info("Adding data");
+
+    storage.setItem("key0", "value0");
+    storage.clear();
+    storage.setItem("key1", "value1");
+    storage.removeItem("key1");
+    storage.setItem("key2", "value2");
+
+    info("Closing storage");
+
+    storage.close();
+  }
+}
+
+function exportShadowDatabase(name)
+{
+  info("Verifying shadow database");
+
+  let profileDir = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  let shadowDatabase = profileDir.clone();
+  shadowDatabase.append("webappsstore.sqlite");
+
+  let exists = shadowDatabase.exists();
+  ok(exists, "Shadow database does exist");
+
+  info("Copying shadow database");
+
+  let currentDir = Services.dirsvc.get("CurWorkD", Ci.nsIFile);
+  shadowDatabase.copyTo(currentDir, name);
+}
+
+function importShadowDatabase(name)
+{
+  info("Verifying shadow database");
+
+  let currentDir = Services.dirsvc.get("CurWorkD", Ci.nsIFile);
+  let shadowDatabase = currentDir.clone();
+  shadowDatabase.append(name);
+
+  let exists = shadowDatabase.exists();
+  if (!exists) {
+    return false;
+  }
+
+  info("Copying shadow database");
+
+  let profileDir = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  shadowDatabase.copyTo(profileDir, "webappsstore.sqlite");
+
+  return true;
+}
+
+function verifyData(clearedOrigins)
+{
+  for (let i = 0; i < principalInfos.length; i++) {
+    let principalInfo = principalInfos[i];
+    let principal = getPrincipal(principalInfo.url, principalInfo.attrs);
+
+    info("Getting storage");
+
+    let storage = getLocalStorage(principal);
+
+    info("Verifying data");
+
+    if (clearedOrigins.includes(i)) {
+      ok(storage.getItem("key2") == null, "Correct value");
+    } else {
+      ok(storage.getItem("key0") == null, "Correct value");
+      ok(storage.getItem("key1") == null, "Correct value");
+      ok(storage.getItem("key2") == "value2", "Correct value");
+    }
+
+    info("Closing storage");
+
+    storage.close();
+  }
+}

dom/localstorage/test/unit/head.js

@@ -0,0 +1,271 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+const NS_ERROR_DOM_QUOTA_EXCEEDED_ERR = 22;
+
+ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+function is(a, b, msg)
+{
+  Assert.equal(a, b, msg);
+}
+
+function ok(cond, msg)
+{
+  Assert.ok(!!cond, msg);
+}
+
+function run_test()
+{
+  runTest();
+};
+
+if (!this.runTest) {
+  this.runTest = function()
+  {
+    do_get_profile();
+
+    enableTesting();
+
+    Assert.ok(typeof testSteps === "function",
+              "There should be a testSteps function");
+    Assert.ok(testSteps.constructor.name === "AsyncFunction",
+              "testSteps should be an async function");
+
+    registerCleanupFunction(resetTesting);
+
+    add_task(testSteps);
+
+    // Since we defined run_test, we must invoke run_next_test() to start the
+    // async test.
+    run_next_test();
+  }
+}
+
+function returnToEventLoop()
+{
+  return new Promise(function(resolve) {
+    executeSoon(resolve);
+  });
+}
+
+function enableTesting()
+{
+  Services.prefs.setBoolPref("dom.storage.testing", true);
+  Services.prefs.setBoolPref("dom.quotaManager.testing", true);
+}
+
+function resetTesting()
+{
+  Services.prefs.clearUserPref("dom.quotaManager.testing");
+  Services.prefs.clearUserPref("dom.storage.testing");
+}
+
+function setGlobalLimit(globalLimit)
+{
+  Services.prefs.setIntPref("dom.quotaManager.temporaryStorage.fixedLimit",
+                            globalLimit);
+}
+
+function resetGlobalLimit()
+{
+  Services.prefs.clearUserPref("dom.quotaManager.temporaryStorage.fixedLimit");
+}
+
+function setOriginLimit(originLimit)
+{
+  Services.prefs.setIntPref("dom.storage.default_quota", originLimit);
+}
+
+function resetOriginLimit()
+{
+  Services.prefs.clearUserPref("dom.storage.default_quota");
+}
+
+function getOriginUsage(principal)
+{
+  let request = Services.qms.getUsageForPrincipal(principal, function() { });
+
+  return request;
+}
+
+function clear()
+{
+  let request = Services.qms.clear();
+
+  return request;
+}
+
+function clearOriginsByPattern(pattern)
+{
+  let request = Services.qms.clearStoragesForOriginAttributesPattern(pattern);
+
+  return request;
+}
+
+function clearOriginsByPrefix(principal, persistence)
+{
+  let request =
+    Services.qms.clearStoragesForPrincipal(principal, persistence, null, true);
+
+  return request;
+}
+
+function clearOrigin(principal, persistence)
+{
+  let request = Services.qms.clearStoragesForPrincipal(principal, persistence);
+
+  return request;
+}
+
+function reset(callback)
+{
+  let request = Services.qms.reset();
+  request.callback = callback;
+
+  return request;
+}
+
+function resetOrigin(principal)
+{
+  let request =
+    Services.qms.resetStoragesForPrincipal(principal, "default", "ls");
+
+  return request;
+}
+
+function installPackage(packageName)
+{
+  let directoryService = Cc["@mozilla.org/file/directory_service;1"]
+                         .getService(Ci.nsIProperties);
+
+  let currentDir = directoryService.get("CurWorkD", Ci.nsIFile);
+
+  let packageFile = currentDir.clone();
+  packageFile.append(packageName + ".zip");
+
+  let zipReader = Cc["@mozilla.org/libjar/zip-reader;1"]
+                  .createInstance(Ci.nsIZipReader);
+  zipReader.open(packageFile);
+
+  let entryNames = [];
+  let entries = zipReader.findEntries(null);
+  while (entries.hasMore()) {
+    let entry = entries.getNext();
+    entryNames.push(entry);
+  }
+  entryNames.sort();
+
+  for (let entryName of entryNames) {
+    let zipentry = zipReader.getEntry(entryName);
+
+    let file = getRelativeFile(entryName);
+
+    if (zipentry.isDirectory) {
+      file.create(Ci.nsIFile.DIRECTORY_TYPE, parseInt("0755", 8));
+    } else {
+      let istream = zipReader.getInputStream(entryName);
+
+      var ostream = Cc["@mozilla.org/network/file-output-stream;1"]
+                    .createInstance(Ci.nsIFileOutputStream);
+      ostream.init(file, -1, parseInt("0644", 8), 0);
+
+      let bostream = Cc['@mozilla.org/network/buffered-output-stream;1']
+                     .createInstance(Ci.nsIBufferedOutputStream);
+      bostream.init(ostream, 32768);
+
+      bostream.writeFrom(istream, istream.available());
+
+      istream.close();
+      bostream.close();
+    }
+  }
+
+  zipReader.close();
+}
+
+function getProfileDir()
+{
+  let directoryService =
+    Cc["@mozilla.org/file/directory_service;1"].getService(Ci.nsIProperties);
+
+  return directoryService.get("ProfD", Ci.nsIFile);
+}
+
+// Given a "/"-delimited path relative to the profile directory,
+// return an nsIFile representing the path.  This does not test
+// for the existence of the file or parent directories.
+// It is safe even on Windows where the directory separator is not "/",
+// but make sure you're not passing in a "\"-delimited path.
+function getRelativeFile(relativePath)
+{
+  let profileDir = getProfileDir();
+
+  let file = profileDir.clone();
+  relativePath.split('/').forEach(function(component) {
+    file.append(component);
+  });
+
+  return file;
+}
+
+function repeatChar(count, ch) {
+  if (count == 0) {
+    return "";
+  }
+
+  let result = ch;
+  let count2 = count / 2;
+
+  // Double the input until it is long enough.
+  while (result.length <= count2) {
+    result += result;
+  }
+
+  // Use substring to hit the precise length target without using extra memory.
+  return result + result.substring(0, count - result.length);
+}
+
+function getPrincipal(url, attrs)
+{
+  let uri = Services.io.newURI(url);
+  if (!attrs) {
+    attrs = {};
+  }
+  return Services.scriptSecurityManager.createCodebasePrincipal(uri, attrs);
+}
+
+function getCurrentPrincipal()
+{
+  return Cc["@mozilla.org/systemprincipal;1"].createInstance(Ci.nsIPrincipal);
+}
+
+function getLocalStorage(principal)
+{
+  if (!principal) {
+    principal = getCurrentPrincipal();
+  }
+
+  return Services.domStorageManager.createStorage(null, principal, "");
+}
+
+function requestFinished(request) {
+  return new Promise(function(resolve, reject) {
+    request.callback = function(request) {
+      if (request.resultCode == Cr.NS_OK) {
+        resolve(request.result);
+      } else {
+        reject(request.resultCode);
+      }
+    }
+  });
+}
+
+function loadSubscript(path)
+{
+  let file = do_get_file(path, false);
+  let uri = Services.io.newFileURI(file);
+  Services.scriptloader.loadSubScript(uri.spec);
+}

dom/localstorage/test/unit/test_archive.js

@@ -0,0 +1,76 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+async function testSteps()
+{
+  const lsArchiveFile = "storage/ls-archive.sqlite";
+
+  const principalInfo = {
+    url: "http://example.com",
+    attrs: {}
+  };
+
+  function checkStorage()
+  {
+    let principal = getPrincipal(principalInfo.url, principalInfo.attrs);
+    let storage = getLocalStorage(principal);
+    try {
+      storage.open();
+      ok(true, "Did not throw");
+    } catch(ex) {
+      ok(false, "Should not have thrown");
+    }
+  }
+
+  info("Setting pref");
+
+  Services.prefs.setBoolPref("dom.storage.next_gen", true);
+
+  // Profile 1 - Archive file is a directory.
+  info("Clearing");
+
+  let request = clear();
+  await requestFinished(request);
+
+  let archiveFile = getRelativeFile(lsArchiveFile);
+
+  archiveFile.create(Ci.nsIFile.DIRECTORY_TYPE, parseInt("0755", 8));
+
+  checkStorage();
+
+  // Profile 2 - Corrupted archive file.
+  info("Clearing");
+
+  request = clear();
+  await requestFinished(request);
+
+  let ostream = Cc["@mozilla.org/network/file-output-stream;1"]
+                .createInstance(Ci.nsIFileOutputStream);
+  ostream.init(archiveFile, -1, parseInt("0644", 8), 0);
+  ostream.write("foobar", 6);
+  ostream.close();
+
+  checkStorage();
+
+  // Profile 3 - Nonupdateable archive file.
+  info("Clearing");
+
+  request = clear();
+  await requestFinished(request);
+
+  info("Installing package");
+
+  // The profile contains storage.sqlite and storage/ls-archive.sqlite
+  // storage/ls-archive.sqlite was taken from FF 54 to force an upgrade.
+  // There's just one record in the webappsstore2 table. The record was
+  // modified by renaming the origin attribute userContextId to userContextKey.
+  // This triggers an error during the upgrade.
+  installPackage("archive_profile");
+
+  let fileSize = archiveFile.fileSize;
+  ok(fileSize > 0, "archive file size is greater than zero");
+
+  checkStorage();
+}

dom/localstorage/test/unit/test_databaseShadowing1.js

@@ -0,0 +1,23 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+loadSubscript("databaseShadowing-shared.js");
+
+async function testSteps()
+{
+  enableNextGenLocalStorage();
+
+  storeData();
+
+  verifyData([]);
+
+  // Wait for all database connections to close.
+  let request = reset();
+  await requestFinished(request);
+
+  exportShadowDatabase("shadowdb.sqlite");
+
+  // The shadow database is now prepared for test_databaseShadowing2.js
+}

dom/localstorage/test/unit/test_databaseShadowing2.js

@@ -0,0 +1,19 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+loadSubscript("databaseShadowing-shared.js");
+
+async function testSteps()
+{
+  // The shadow database was prepared in test_databaseShadowing1.js
+
+  disableNextGenLocalStorage();
+
+  if (!importShadowDatabase("shadowdb.sqlite")) {
+    return;
+  }
+
+  verifyData([]);
+}

dom/localstorage/test/unit/test_databaseShadowing_clearOrigin1.js

@@ -0,0 +1,30 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+loadSubscript("databaseShadowing-shared.js");
+
+async function testSteps()
+{
+  enableNextGenLocalStorage();
+
+  storeData();
+
+  verifyData([]);
+
+  let principal = getPrincipal("http://origin.test", {});
+  let request = clearOrigin(principal, "default");
+  await requestFinished(request);
+
+  verifyData([1]);
+
+  // Wait for all database connections to close.
+  request = reset();
+  await requestFinished(request);
+
+  exportShadowDatabase("shadowdb_clearedOrigin.sqlite");
+
+  // The shadow database is now prepared for
+  // test_databaseShadowing_clearOrigin2.js
+}

dom/localstorage/test/unit/test_databaseShadowing_clearOrigin2.js

@@ -0,0 +1,19 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+loadSubscript("databaseShadowing-shared.js");
+
+async function testSteps()
+{
+  // The shadow database was prepared in test_databaseShadowing_clearOrigin1.js
+
+  disableNextGenLocalStorage();
+
+  if (!importShadowDatabase("shadowdb-clearedOrigin.sqlite")) {
+    return;
+  }
+
+  verifyData([1]);
+}

dom/localstorage/test/unit/test_databaseShadowing_clearOriginsByPattern1.js

@@ -0,0 +1,29 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+loadSubscript("databaseShadowing-shared.js");
+
+async function testSteps()
+{
+  enableNextGenLocalStorage();
+
+  storeData();
+
+  verifyData([]);
+
+  let request = clearOriginsByPattern(JSON.stringify({ userContextId: 15 }));
+  await requestFinished(request);
+
+  verifyData([4,5,6]);
+
+  // Wait for all database connections to close.
+  request = reset();
+  await requestFinished(request);
+
+  exportShadowDatabase("shadowdb-clearedOriginsByPattern.sqlite");
+
+  // The shadow database is now prepared for
+  // test_databaseShadowing_clearOriginsByPattern2.js
+}

dom/localstorage/test/unit/test_databaseShadowing_clearOriginsByPattern2.js

@@ -0,0 +1,20 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+loadSubscript("databaseShadowing-shared.js");
+
+async function testSteps()
+{
+  // The shadow database was prepared in
+  // test_databaseShadowing_clearOriginsByPattern1.js
+
+  disableNextGenLocalStorage();
+
+  if (!importShadowDatabase("shadowdb-clearedOriginsByPattern.sqlite")) {
+    return;
+  }
+
+  verifyData([4,5,6]);
+}